# Anyone look into the inside of folding knives on the construction?



## Alan0354 (Oct 17, 2022)

Hi

This is about the inside of the folding knives, their design and construction, more on engineering technical side. I want to see other people hear have any suggestions which knife is strong in what I am going to describe in the following.

I actually posted this in "All about pocket knives" Knife Mechanic's Swap forum that is supposed to talk about the mechanical aspect of knives. When I described using the knife for prying, thrusting ans shanking, they called me vigilantism!!! So I try posting here to see if anyone actually like me opening up the knife and study the construction, and any suggestion which model that is good. So here it is:


Just curious anyone here are like me that open the knives up and look at the inside? I find quite a few that I opened are *quite disturbing*. A lot of folding pocket knives look very heavy duty on the outside. But if you open them up and look at the inside, it's a totally different story. I am looking at the* joint between the handle and the blade*, here is the picture of what I am looking:





The picture show the thickness of the blade where it is screwed onto the frame. You can see the cut out to fit the ball bearings. This picture is Off-Grid Baby Rhino. The thickness is* 0.073"*, which is very robust. The two steel side plate is *0.06" *thick. All in all, this is a very robust knife that can stand up to prying, shanking and all that.


Now, look at the SenCut Acumen : https://www.amazon.com/dp/B09F6D95SC?psc=1&ref=ppx_yo2ov_dt_b_product_details

Looks heavy duty from the looks, BUT, look at the inside:




The thickness is only *0.035"*, That's very thin for a knife that's supposed to be heavy duty by the looks.



You cannot even trust the brands that stress on heavy duty. Like the Off-Grid Enforcer.
https://www.amazon.com/dp/B09RQ7T3Y7?psc=1&ref=ppx_yo2ov_dt_b_product_details




The thickness of the blade pointed by GREEN arrow is good......BUT, *look at the metal frame of the handle*. They made the pocket for the ball bearing into the frame, look at the picture on the two RED arrow. *It's very thin, like paper.* How to you expect this to survive prying and heavy use in survival situation? *You cannot even look a one model of the brand to judge the other models. Like the Off-Grid Baby Rhino, the picture above show it's as good as it gets. And this one is the worst!!!*


Kubey is the same, I have the KU159 DUGU, it's robust with *0.063"* thick on the blade and* 0.06" *on the frame, but then I bought and return the KU901, it's THIN!!!

What's wrong with the people that design knives, they don't seems to have any common sense. it's so easy to design a study knife, how can they be so stupid.



All that said, if anyone actually opened knives and have any recommendation, let me know.

Thanks


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## Alan0354 (Oct 17, 2022)

I am open to look at knives without blade pivot ball bearing. The one brand I found so far is Steel Will. What other brand has knife with no ball bearing? without ball bearing, that part of concern won't be too thin.


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## Dirty Dog (Oct 17, 2022)

So, when you put them back together and actually tested them, how did they perform?

Ball bearings make the knife easy to open. And folding knives are never going to make good crowbars. Neither do fixed blade knives, really. Knives are for cutting and poking. If you want a crowbar... get a crowbar.

For the record, I started forging fixed blade weapons, from daggers to swords, about 30 years ago. I have not made any swords in maybe 15 years. For the last 10-ish years, I've made fixed blades knives of various sorts using stock removal techniques. About 4 years ago I started doing folders, mostly liner lock designs. I've attempted a few assisted opening knives, but have not been particularly happy with the results. I own a number of automatic knives, mostly Benchmade and Microtech, but I have never attempted to make one.

If you want a good carry knife, suitable for anything from trimming a hangnail, to opening the mail, or opening an attacker, there are about a bazillion good choices. None of them will work well as a crowbar. On the budget end, I like Spyderco. On the "no holds barred" end, I like Microtech and Benchmade. My own EDC knives are a Microtech Ultratech or a Benchmade Infidel. I'm also quite fond of the Benchmade Auto-stryker, but I do not believe it is currently being produced.


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## Alan0354 (Oct 17, 2022)

Good that you do forging and all. I don't know anything about knife making, just looking a finish products and do sharpening. None of the knives I bought is that sharp, I have to sharpen all of them to make it sharp. The whole area where I live(Bayarea), I don't think you can find a house so remote that it won't disturb the neighbor when one starts hammering!!! Not even houses of $10M+, houses are just too close together. It's not possible to have a forge shop in the Bayarea.

It's easy to take pocket knives apart and put them back together. they perform exactly the same, no slack and all that. Really only tools needed are a few T6, T7 and T8 Torx. But it's funny I bought 3 sets, they all a little different in size, it's like I have to test which one have the tightest fit to the screw even though they all supposed to be either T6, T7 or T8!!! I even look whether they have in between size or something like SAE vs metric!!! You use the wrong one, you can strip the screw easily.

I just feel if I get a knife, I want to use it like all-in-one tool, for prying, cutting and everything else. The point I want to make in the thread is they COULD HAVE easily make it much sturdy. Why don't they even stop and think.

I looked at the knives you suggested, Microtech and Benchmade are too expensive. I am looking for price range between *$40 to $70*, which I should have a lot of choices. Even the lower price is not that bad. I am not looking for HRC>60. I rather have more toughness than edge retention as I don't want the blade to crack and break off. For EDC, I don't even use it for opening envelope or anything. I sharpen it and just carry it. Like *D2, N690, 9Cr13Mov* etc. is about as high HRC I would like to go. Those are in price range of $40 to $70.

I am looking for* 3.1 to 3.25" blade* max. I have a Kubey Dugo KU159 that is 2.91" that fits my requirement already so the range I am looking for is very narrow.

More importantly, I want the knife to a longer flipper TAP to prevent the knife from shoving back into my hand when I do shanking and thrusting. This is very important for me as shown in this picture.



You see the curve I marked with RED, this is where my index finger is, the flipper of the blade serves to prevent the knife from being shoved back into the hand when thrusting. I look at the few brands of knives you suggested, they mostly don't have that.

The problem with knives is you CANNOT judge by looking at the outside. This picture is the Sencut Acumen:https://www.amazon.com/dp/B09F6D95SC?psc=1&ref=ppx_yo2ov_dt_b_product_details

Just look at the outside, it looks like heavy duty, survival type, and it's emphasized it is. BUT, look at how thin the part is when I opened it and took picture, it's only 0.035" thick!!!!





One cannot go by the looks, NOT even by the brand. Like the Kubey KU159 I have, that part is a robust 0.063" thick, but I bought the KU109, it's as thin as the Sancut. I returned it.

That's the reason, I am not looking for people's suggestions *UNLESS they actually opened it and look at it *to tell me. Or else it's all a blind guess.

Thank you for replying without criticizing. Do you know I got quote religion when I post this question in the other knife forum, and I was called vigilante for talking about thrusting and shanking!!! That was in the mechanical part of the knife forum!!! That's why I post it here so maybe I have more luck!!!

I know I am very nitpicking, but I think it makes sense for my concern if I want an all-in-one survival knife. It's not too muck to ask. *I actually bought*:

1) OFF-Grid Baby Rhino with 2.5" blade:https://www.amazon.com/dp/B09JL64NDT?psc=1&ref=ppx_yo2ov_dt_b_product_details  with 0.073" thickness.

2)Kubey KU159 Dugu with 2.91" blade:https://www.amazon.com/dp/B09ZPCFLGJ?psc=1&ref=ppx_yo2ov_dt_b_product_details with 0.063" thickness.

3) LAURISILVA with 3.25" blade: https://www.amazon.com/gp/product/B09G2FNM5C/ref=ox_sc_saved_image_4?smid=A3KWTOBYJBR9AN&th=1  with 0.053" thickness.

I just want to find one more in 3.1" to 3.25" range. It is out there, it's not impossible to find. I just hope I don't have to keep buying and returning to find another one.


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## wab25 (Oct 18, 2022)

Ever watched Forged in Fire? They make bladed weapons and put them through extreme tests. What is interesting is that the bigger, thicker, heavier duty blade is not always the blade that survives the tests. Many times its the smaller and lighter blade that handles the extreme tests better... its almost like there is more than one variable that contributes to the quality of the blade.

That said... it might be interesting for you to do some testing with your assortment of knives. Rig up a pry test, and see how much force is required to break the blade.... do this for the thin one and the robust thick one. 

There are three things I would look for. First, what is the actual difference in the amount of force needed to make the blade fail? Second, is a person able to generate that amount of force? Finally, where does the blade actually fail? This is important... if the blade fails somewhere other than area where you are measuring.... then the area you are measuring is not the limiting factor. This means it won't matter if one if thinner than the other... if that is not the point of failure.

If you want to get into the science of it.... do some experiments, and gather some real data. Right now we are just operating on an assumption that the failure point of the blade is the where the ball bearing joint goes. If that is not the failure point... then the only thing you gain by making that part thicker, is weight.


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## tkdroamer (Oct 18, 2022)

Alan0354 said:


> Hi
> 
> This is about the inside of the folding knives, their design and construction, more on engineering technical side. I want to see other people hear have any suggestions which knife is strong in what I am going to describe in the following.
> 
> ...


If I am understanding the disassembled knives correctly, the area you are pointing does not what support all of the force in a lateral or twisting motion. Which is a quick recipe for a broken blade. Hardness of the blade is going to play a Big factor. 
The cross-section you are pointing at is thicker than the width of the blade and the rules of steel properties say it is as strong as it is going to get.


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## Dirty Dog (Oct 18, 2022)

Alan0354 said:


> Good that you do forging and all. I don't know anything about knife making, just looking a finish products and do sharpening. None of the knives I bought is that sharp, I have to sharpen all of them to make it sharp. The whole area where I live(Bayarea), I don't think you can find a house so remote that it won't disturb the neighbor when one starts hammering!!! Not even houses of $10M+, houses are just too close together. It's not possible to have a forge shop in the Bayarea.


Sure you can. Acoustic panels and other forms of sound dampening are readily available.
That said, I do not believe there is any need to forge small blades. The benefits of forging are mostly applicable only to large blades. Stock removal and a good heat treat will yield an outstanding blade.


Alan0354 said:


> I just feel if I get a knife, I want to use it like all-in-one tool, for prying, cutting and everything else.


You can feel anything you like, but that's not how it works. The right tool for the job. Using your own example, if you use the wrong size bit, you will destroy the screw. If you use a knife as a crowbar, you will destroy the knife.


Alan0354 said:


> I looked at the knives you suggested, Microtech and Benchmade are too expensive.


If you want a Ferrari, you have to pay for a Ferrari. You can get a 74 Vega with 280,000 miles on it for cheap. But it's not really reasonable to complain that it won't perform like the Ferrari.


Alan0354 said:


> I am looking for price range between *$40 to $70*, which I should have a lot of choices.


You do. Millions. But none of them will work as a crowbar. If you want tools other than what a knife is intended to do, maybe get a multitool. I like Gerber. Every car anybody in my family owns has one in the glovebox or center console.


Alan0354 said:


> Even the lower price is not that bad. I am not looking for HRC>60. I rather have more toughness than edge retention as I don't want the blade to crack and break off.


It won't, if you use it for a knife.


Alan0354 said:


> For EDC, I don't even use it for opening envelope or anything. I sharpen it and just carry it.


So you want a knife that can do everything, but you don't actually use it for those things. 


Alan0354 said:


> Like *D2, N690, 9Cr13Mov* etc. is about as high HRC I would like to go. Those are in price range of $40 to $70.


Those, like any other material, are in the price range of $5 to $20,000.
The Infidel, for example, which you say is too expensive. The standard blade for that knife is D2 with an HRC of 60-62. Mine is a limited run offering with a CPM-S30V blade. The HRC is 58-60.
The blade material is a minor factor in determining the price of a knife.

Taking a knife apart and taking measurements doesn't really tell you much. If you want to know if the knife is any good, *use it for the intended purpose*. If you insist on using it as a crowbar, a folder will always be your absolute worst choice. Get a fixed blade knife with a thick blade and a full tang. You will still destroy it, but it will last longer than any folder.


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## Alan0354 (Oct 18, 2022)

wab25 said:


> Ever watched Forged in Fire? They make bladed weapons and put them through extreme tests. What is interesting is that the bigger, thicker, heavier duty blade is not always the blade that survives the tests. Many times its the smaller and lighter blade that handles the extreme tests better... its almost like there is more than one variable that contributes to the quality of the blade.
> 
> That said... it might be interesting for you to do some testing with your assortment of knives. Rig up a pry test, and see how much force is required to break the blade.... do this for the thin one and the robust thick one.
> 
> ...


Yeh, but remember, I pay for every one of them, I don't want to buy, then destroy it.

Besides, that's physics and engineering which I am. You can use common sense to look at the weak point, with 0.03" thick at that point, I cannot imagine the other parts along the knife would be a weaker point, you are talking about a solid blade on one side, and the handle with 2 metal side plates on the other side. blade and handle join together only at that one point. This is common sense, I don't need to pry to break to prove that.

Just think about, the blade is at least 0.11" thick solid, the handle has TWO metal sides each of 0.06" thick sandwiching the blade. You don't need to be an engineer to tell where is the weak point!!! Just common sense.

Most importantly*, There are good ones around* that fit what I want. My question is *NOT* whether what I want is justifiable. My question is ANYONE open their knives and find one that fits what I want.

Like I said, *I have 3 *of them that looks good as I posted in detail in *post #4*. I just don't want to buy, then return, that's not very nice. So I rather see whether anyone opened their knives and can tell me one that is good.

If no one open their knives, then I just move on to buy and return.


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## drop bear (Oct 18, 2022)

Alan0354 said:


> Yeh, but remember, I pay for every one of them, I don't want to buy, then destroy it.
> 
> Besides, that's physics and engineering which I am. You can use common sense to look at the weak point, with 0.03" thick at that point, I cannot imagine the other parts along the knife would be a weaker point, you are talking about a solid blade on one side, and the handle with 2 metal side plates on the other side. blade and handle join together only at that one point. This is common sense, I don't need to pry to break to prove that.
> 
> ...



I don't open knives. But there is a guy Nick shebazz on youtube who does.


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## Alan0354 (Oct 18, 2022)

I want to put in separate post.  I am not asking to justify what I want and concern. I just ask who open their knives and can tell me what they have opened that fit what I want. I am not here to talk whether it's justifiable. If nobody have suggestions, then I just go on youtube to find as much video on disassembly or buy/return.


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## Alan0354 (Oct 18, 2022)

drop bear said:


> I don't open knives. But there is a guy Nick shebazz on youtube who does.


Yeh,  I search through a lot of his videos already. Most are bigger than the ones I want. I already search up and down youtube already, they just don't do those with blades around 3.1 to 3.25".

Ha ha, I even look at those in 3.5" range, you'd be surprise how many of them are very thin in that area.


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## Alan0354 (Oct 18, 2022)

Actually, since I have no luck in doing research and asking question. I just contact Amazon about my situation on buying and return knives, they gave me an ok.

I guess my problem is solved for now!!!


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## wab25 (Oct 18, 2022)

Alan0354 said:


> Ha ha, I even look at those in 3.5" range, you'd be surprise how many of them *are very thin in that area*.


What data do we have that show that this area is the failure point? Or are we just assuming that is the failure point?


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## Alan0354 (Oct 18, 2022)

wab25 said:


> What data do we have that show that this area is the failure point? Or are we just assuming that is the failure point?


Like I said, it's common engineering, look at the weakest link along the knife. I don't know how else to explain it.


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## wab25 (Oct 18, 2022)

Alan0354 said:


> Like I said, it's common engineering, look at the weakest link along the knife. I don't know how else to explain it.


So, no data. Got it.

I found some data... yes its a small data set, but it is more than none....






Interestingly.... none of those knives broke in the area that you are measuring.... From this data, I would not think that where the bearing is, is the weak point, for prying with the knife. It looks much more probable, that the blade breaks long before the joint fails.... In fact, that joint did not break once out of these knives....

But, here I am using data again..... Don't engineers use data?


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## Alan0354 (Oct 18, 2022)

Like I said, I am not interested in arguing anymore, there are knives out there that are robust, You don't know how those look inside. Those tested are BIG knives and maybe they are robust inside, nobody knows. This is ONLY a problem with the new type of knives with ball bearing pivot, the older ones without ball bearing will NOT have problem. Also, REMEMBER, I am looking for 3.1" to 3.25" blade, not those 4" to 5" big knives. I put it very clear from the beginning.

I want to find one that is beefy there, you don't have the data, just leave it. 

Tip is another potential problem if it taper down too much, That's why I more look at tanto type.

BTW, I would NOT look for any of those in demo also as I described in post #4. I want those with large curve for safety.


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## Alan0354 (Oct 18, 2022)

I actually posted the question on that youtube and ask whether he can come back and tell people which one has ball bearing pivot and which one doesn't. That will make a day and night difference. It would NOT be a problem if it has no ball bearing. That's very obvious.

That's why I am seriously consider Steel Will Laner that uses bronze bearing that is a lot thinner, that they don't have to thin out the critical part.

As I said, NOT all the ones have ball bearing is weak there. It's like half and half. The 3 I mentioned I have are beefy and can perform well also.

The Ruike P801 in the video is 3.5", I will keep that in mind. I looked everywhere, there is NO description that it has ball bearing. I post that on Amazon, we'll see what is the answer. I'll keep that in mind even though it's longer than I want.

Ontario Par2 definitely no ball bearings. It's bronze bearing, it should be strong in that part.

KerShaw Emerson CQC 10K don't have a disassembly video, but the 6K is nylon washer, no ball bearing.

I doubt Ka Bar Dozier has ball bearing.


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## Wing Woo Gar (Oct 18, 2022)

Alan0354 said:


> I am open to look at knives without blade pivot ball bearing. The one brand I found so far is Steel Will. What other brand has knife with no ball bearing? without ball bearing, that part of concern won't be too thin.


Benchmade? Microtech? Chris Reeves? Those are my go to brands. I have been happy with all of them. Microtech is a fine tool and not something I would pry with. I work my Benchmade folders pretty hard. I have a fixed blade “pacific” from Chris Reeves that is rock solid and far more durable than anything I would ever need. Keep in mind that Microtech and Chris Reeves knives can set you back anywhere from $350.00 to $3,500.00 depending on model and materials. Benchmade is more reasonable for a work tool in general and are guaranteed. I am picky (persnickety even) and have never had a failure to function so that’s my best experience based advice.


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## Wing Woo Gar (Oct 18, 2022)

As for price, I’m a buy once, cry once kind of guy. I’m willing to pay for a high quality tool. 


Alan0354 said:


> Good that you do forging and all. I don't know anything about knife making, just looking a finish products and do sharpening. None of the knives I bought is that sharp, I have to sharpen all of them to make it sharp. The whole area where I live(Bayarea), I don't think you can find a house so remote that it won't disturb the neighbor when one starts hammering!!! Not even houses of $10M+, houses are just too close together. It's not possible to have a forge shop in the Bayarea.
> 
> It's easy to take pocket knives apart and put them back together. they perform exactly the same, no slack and all that. Really only tools needed are a few T6, T7 and T8 Torx. But it's funny I bought 3 sets, they all a little different in size, it's like I have to test which one have the tightest fit to the screw even though they all supposed to be either T6, T7 or T8!!! I even look whether they have in between size or something like SAE vs metric!!! You use the wrong one, you can strip the screw easily.
> 
> ...


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## Alan0354 (Oct 18, 2022)

That's way too expensive. I am too cheap for that. Also, a lot of study knives are not that expensive.


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## Alan0354 (Oct 18, 2022)

That's way too expensive. I am too cheap for that. Also, a lot of study knives are not that expensive.

Like I said over and over,* My demand is NOT unreasonable*. Based on result, almost 1/2 of the knives I bought is good. Problem is there's no way to tell unless opening it. AND you cannot buy a different model of the same brand even if you have one that is really good. Case in point the OFF-GRID Baby Rhino is the best, but the Enforce is crab.


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## jks9199 (Oct 18, 2022)

May I suggest that you aren't looking at the physics and stresses on the blade properly.  You've taken apart some knives, and decided that the ball bearing design is too thin.  Maybe some research into lock design and methods will help... 

Of course, if you insist on using a knife as a pry bar, screwdriver, hammer, or pretty much anything other than a knife... There's no folder that'll do you well...  For that matter, even a full tang will fail you eventually.

Good piece on locks: 13 Types of Knife Locking Mechanisms (with Pictures) - Marine Approved
Another: Folding Knife Lock Types Guide | KnivesAdvice
30 minutes of info... with moving pictures.:


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## Dirty Dog (Oct 18, 2022)

wab25 said:


> What data do we have that show that this area is the failure point? Or are we just assum





Wing Woo Gar said:


> Benchmade? Microtech? Chris Reeves? Those are my go to brands. I have been happy with all of them. Microtech is a fine tool and not something I would pry with. I work my Benchmade folders pretty hard. I have a fixed blade “pacific” from Chris Reeves that is rock solid and far more durable than anything I would ever need. Keep in mind that Microtech and Chris Reeves knives can set you back anywhere from $350.00 to $3,500.00 depending on model and materials. Benchmade is more reasonable for a work tool in general and are guaranteed. I am picky (persnickety even) and have never had a failure to function so that’s my best experience based advice.


Add Cold Steel to the list. They've got a reputation for solid work, and they're cheap, compared to the good stuff. Heck, Gerber and Buck make some decent, usable knives, and they're quite cheap.


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## Dirty Dog (Oct 18, 2022)

Alan0354 said:


> That's way too expensive. I am too cheap for that. Also, a lot of study knives are not that expensive.
> 
> Like I said over and over,* My demand is NOT unreasonable*.


You can say it over and over and over and over. Doesn't make it true. Expecting a small, cheap, folding knife to perform crowbar duty is unreasonable.


Alan0354 said:


> Based on result, almost 1/2 of the knives I bought is good.


You can say that over and over too. But until you do more than just look at them, you don't really have a clue if they're any good or not.


Alan0354 said:


> Problem is there's no way to tell unless opening it.


Yes, there is. You can tell how good they are *without* disassembling them. It's called using them. A real world evaluation is a bazillion times more worthwhile than just looking at it.


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## Alan0354 (Oct 18, 2022)

Dirty Dog said:


> You can say it over and over and over and over. Doesn't make it true. Expecting a small, cheap, folding knife to perform crowbar duty is unreasonable.
> 
> You can say that over and over too. But until you do more than just look at them, you don't really have a clue if they're any good or not.
> 
> Yes, there is. You can tell how good they are *without* disassembling them. It's called using them. A real world evaluation is a bazillion times more worthwhile than just looking at it.


This is BS. There goes to show you have no idea about the mechanics and physics. You really have no common sense on how things works. You look at the video on testing, all of them are not expensive knives. Just most of them don't have ball bearings.

Please stop and read and THINK instead of start out by putting people down. You should be better than that to say only expensive knives are better. You have NO IDEA about physics.


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## Alan0354 (Oct 18, 2022)

Dirty Dog said:


> Add Cold Steel to the list. They've got a reputation for solid work, and they're cheap, compared to the good stuff. Heck, Gerber and Buck make some decent, usable knives, and they're quite cheap.


So is OFF-GRID knives. You have NO IDEA about physics how to look at the weak points. In the video, it shows the tip of the blade can be a weak point. OF CAUSE, that's common sense. BUT there can be other weak points and I am looking at it also. THAT'S WHY ALL THE ONE I CHOSE IS TANTO OR WIDER KNIVES so the blade is not pointy and narrow. That's why I did not talk about it. IT'S COVERED!!!

I am trying to stay very objective and be polite with you. BUT you are really testing me. You have NO IDEA what you are talking just like gun smithing.

I wish people in Physics Forums are into knives, I bet we can really analyze the situation because they have the SCIENTIFIC knowledge. Too bad they don't, it's not their thing.


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## Alan0354 (Oct 18, 2022)

Alan0354 said:


> So is OFF-GRID knives.





jks9199 said:


> May I suggest that you aren't looking at the physics and stresses on the blade properly.  You've taken apart some knives, and decided that the ball bearing design is too thin.  Maybe some research into lock design and methods will help...
> 
> Of course, if you insist on using a knife as a pry bar, screwdriver, hammer, or pretty much anything other than a knife... There's no folder that'll do you well...  For that matter, even a full tang will fail you eventually.
> 
> ...


My question has nothing to do with locking if you read my thread. It's the pivot point that is weaken by the ball bearings.


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## Wing Woo Gar (Oct 18, 2022)

Alan0354 said:


> That's way too expensive. I am too cheap for that. Also, a lot of study knives are not that expensive.
> 
> Like I said over and over,* My demand is NOT unreasonable*. Based on result, almost 1/2 of the knives I bought is good. Problem is there's no way to tell unless opening it. AND you cannot buy a different model of the same brand even if you have one that is really good. Case in point the OFF-GRID Baby Rhino is the best, but the Enforce is crab.


I understand that budget is a concern. Buy, and return if the product is unsatisfactory.


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## Alan0354 (Oct 19, 2022)

Wing Woo Gar said:


> I understand that budget is a concern. Buy, and return if the product is unsatisfactory.


That's what I am going to do. I am trying to be nice, I even communicated with Amazon, they said it's ok, so that's what I am going to do. I am happy.

Too bad people talked about Cold Steel, I don't like anyone of them, I want the flipper tap so I can use the index finger to flip the knife!!! I really don't mind if I have to pay like $80 to $100, just not over $200 like some of the fancy ones. I want a knife that has a long extension to prevent the knife from being pushed back into my hand when I thrust like this picture:





You can see in the picture with the Red mark. This is for safety to prevent the knife from being driven into my hand when I thrust hard(shanking). Cold steel doesn't seem to have that many like that.


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## Alan0354 (Oct 19, 2022)

I look at the Cold Steel AD10, It doesn't have ball bearing, that's the reason this is a strong knife:





It's a decent knife, it's a little long, but I'll keep that in mind. It's about $100, so it's acceptable. Just I want the index finger flipper tap.


I am looking at this one, Steel Will Lennar:
https://www.amazon.com/gp/product/B07QQF1TK6/ref=ox_sc_saved_image_3?smid=AVK2FQXQF9PPN&psc=1

No ball bearing, 3.25"


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## drop bear (Oct 19, 2022)

Alan0354 said:


> So is OFF-GRID knives. You have NO IDEA about physics how to look at the weak points. In the video, it shows the tip of the blade can be a weak point. OF CAUSE, that's common sense. BUT there can be other weak points and I am looking at it also. THAT'S WHY ALL THE ONE I CHOSE IS TANTO OR WIDER KNIVES so the blade is not pointy and narrow. That's why I did not talk about it. IT'S COVERED!!!
> 
> I am trying to stay very objective and be polite with you. BUT you are really testing me. You have NO IDEA what you are talking just like gun smithing.
> 
> I wish people in Physics Forums are into knives, I bet we can really analyze the situation because they have the SCIENTIFIC knowledge. Too bad they don't, it's not their thing.



There are knife forums.


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## Alan0354 (Oct 19, 2022)

drop bear said:


> There are knife forums.


I tried that first already, somehow, everywhere talked about everything else instead of just tell me what did they see when open up their knives. Like I said, I so wish people in Physics Forums are into knives so they know exactly what I am asking for.

My question is so simple, I just want to find anyone that open their knives can tell me if they see anyone that is what I want and give me the name and I'll go look it up. That's it, not asking for opinions or judgement. Just someone that see the inside. I have to explain what I am looking for, thereby all the pictures. It's not to justify whether I am right or wrong. Just describe what I am looking for.


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## tkdroamer (Oct 19, 2022)

Dirty Dog said:


> Sure you can. Acoustic panels and other forms of sound dampening are readily available.
> That said, I do not believe there is any need to forge small blades. The benefits of forging are mostly applicable only to large blades. Stock removal and a good heat treat will yield an outstanding blade.
> 
> You can feel anything you like, but that's not how it works. The right tool for the job. Using your own example, if you use the wrong size bit, you will destroy the screw. If you use a knife as a crowbar, you will destroy the knife.
> ...


I want to see the Vega with 280,000 miles!


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## Wing Woo Gar (Oct 19, 2022)

Alan0354 said:


> That's what I am going to do. I am trying to be nice, I even communicated with Amazon, they said it's ok, so that's what I am going to do. I am happy.
> 
> Too bad people talked about Cold Steel, I don't like anyone of them, I want the flipper tap so I can use the index finger to flip the knife!!! I really don't mind if I have to pay like $80 to $100, just not over $200 like some of the fancy ones. I want a knife that has a long extension to prevent the knife from being pushed back into my hand when I thrust like this picture:
> View attachment 29174
> ...


Look at Benchmade griptilian. It’s very grippy.


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## Alan0354 (Oct 19, 2022)

Wing Woo Gar said:


> Look at Benchmade griptilian. It’s very grippy.


thanks, I just bought the second one of this, I cannot refuse when they are on sale for $24.
https://www.amazon.com/gp/product/B09G2FNM5C/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

Here is the picture of my 3 favorite knives from big to small:




They ALL fit everything I want, the part of the blade of my concern are at least 0.053", side frame of 0.06", wide blade front so it's not easy to break. Long index finger guard show as the RED arch. All heavy duty knives. On the big and the cheapest one at the top of the picture, everything is thick, I don't care how good the quality of the metal of the expensive, nothing beats the sheer thickness of the metal. The blade is 0.14" thick!!! hell, all 3 have 0.14" thick blade.

What I am looking for are not uncommon, just have to know which one. I bought the second big one(on top of the picture) that is 3.25" because that's the compromise between size and effectiveness.......AND price I cannot refuse. It's still a strong D2 steel blade with a lot of good reviews. One doesn't have to pay an arm or a leg for a good one.

Now, I can look for a 3.5" blade. That should be easier to find.


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## Rich Parsons (Oct 19, 2022)

Hi Alan, 

I get physics. Yet physics is not always the answer for the question. 
One knife might be great for the guy with the small farm and horrible for the EMT. 
And yet there could be a knife with a good compromise and good overlap of usage. 

I am a luddite and a fast adapter. 
That means in some areas it takes me forever to engage the new tech, and in other areas I am on the cutting edge. 
It also means that when I find something I have a tendency to stick with it. 

e.g. Emerson Wave Knives are $1xx - $2xx when they were being made and now they are not the blades are going up for more than that on the used market. Or at least they did a year or so ago when I checked. 

They have licensed the Wave Patent / Tech to the cheaper knife makers and one can get a $19-$50 on Amazon. 
That part makes sense and it is cool. 

And for those who have never used an original Emerson Wave, will never understand why after buying and testing them I do not like them. 
The pull is too high a resistance to get a clean and continuous motion and open every time. 

This has to do with some of what you are talking about and taking them apart one can see the difference mainly in the washer quality and tolerances and stack tolerance overall. 

And even if the stack tolerance is within the original spec the material of the components are cheaper and have different mu, or coefficient of friction. The also have a different lubrication or no lubrication. Or if the original had none , the cheaper version may have some to offset the cheaper material (* even if made within the stack tolerance *). 

I and one of my Black Belt students can have this discussion and he can list the washer plastic content and metal content and the differences and ... , I just do not have it memorized like he does. He was in the business of repairing equipment so it was part of his trade. Now he repairs industrial lasers. 

Another example are Glocks (* I am not trying to start a Glock war if you (All posters / readers / lurkers) love them cool for you, I have a different opinion. *) , I was shooting a friends, who meticulous on care and maintenance (He waxes the bucket of his Kubota) and I had a K-B. I would type the letter together as that is the proper term but some Glock fanatics search for it as it stands for K-A-B-O-O-M. Which years ago was a term that was created to have these discussions with the Gen 3. Yes they have fixed any issues since then. 
But I had a .40 cal KB in my hands while it discharged. 

Supposedly , the feed angle is better and the triple internal safety are better. Yet on the handgun TV Show the Glock expert lost just about ever competition and each time and in between he complained so much I had to fast forward through him all the time, that it was the grip angle and he was not used to it. So one company has something they think is better. Some adapt, others who have not bought into only have iPhone and iGear as an example with Glock and only Glocks , and no other manufacturers. . 
So I prefer to not appreciate any cool technology they may have because it takes away from my goals and then the accident / critical failure makes me always wonder , and not trusting a critical tool because of fear of critical failure I choose not to use them. 

Also why I will not have a simple push lock on the back  of a knife as I can grip most of them tightly ( Different discussion on grips in a different thread ) and have the lock be compromised the knife blade will flop free. 
So, finding the person who is into physics or repair and maintenance , or material strength and o the same hobby is a small chance. 

I am not saying do not post. 
Just do not take it personal nor to be upset if people do not share your passion of that topic. 

As to just taking them apart, everything can stack tolerance line up and have decent retention and strength, and still not meet the requirements of the user. 

I like thicker point or tanto (Even half) points to pierce the inside of a door to access a lock or mechanical release. 
I like half serrated for assistance to cut seatbelts and to have the blade be large enough so that the knuckle of the blade when closed is outside my fist grip. So I can use it to shatter a window if required. 

Many EMTs may have a similar need for Seatbelts or clothes and yet the size of the handle I like would be large for most. 
And what most people like would be nothing more than a hidden palm knife for me. 

So the field application to me is more important, and the use case is critical for the review of the tool. Then if two are close or similar in some areas and different in others, then taking it apart to understand why is also good. 

Also taking one apart to make sure its internal designs are good after it has passed the other tests is also a good plan. 
Only for me I see the application and use case studies as more important for the initial discrimination / selection process.


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## Alan0354 (Oct 19, 2022)

I have been trying to clarify, I am *not asking *about what is important for the knife, that's subjective. I was very specific on one specific part of the the knife that I am concern with, *NOT *that it's the most important, it's just my *specific *question. I know different things are important to different people, but that's not this thread is about.

Of cause you can see the video on testing the knives, a few broke the tip of the blade, the shape of the blade is important, BUT that's not the question of this thread. For that, I tend to choose Tanto shape that the tip becomes wider fast  as shown in the picture of my 3 knives.

It's interesting that you mention you want serrated knife, I want that too, it's just hard to find. I want my EDC to be able to cut the seat belt fast. I just found one interesting one:
https://www.amazon.com/gp/product/B09QBVJRY1/ref=ox_sc_saved_title_2?smid=A2X6NDN9Z5CRN7&psc=1

This one also use bronze washer, not ball bearing. So the part I am concern with should be nice and robust without the cutout for the ball bearings.

I don't like the Emerson Wave Knives design that rely on the pants pocket to open the knife. What if it fails to hook onto the pants?!!! I only want flipper tap on the blade so I can flip the knife open with the index finger. Too bad that ruled out Cold Steel. I got to have the tap, it also serves to keep the knife more secure in the hand to prevent the knife being shove back into the hand when thrusting.

Those are all very important features I got to have with the knives, BUT I did not said that BECAUSE I am not asking for what is important, I just asked about the ONE specific thing in this thread. I am NOT asking for opinion, just if anyone open a knife, tell me if they see what I like and let me know the model so I can look at it.

People kept mistaken I was asking for opinion of a knife. then it would be like what you said that everyone has different needs. I think people read part of my post and assumed I was asking for opinion and start telling me that this part is NOT critical. I read your post* 3 times* before I reply back.

Ha ha, I bought a Glock 26, but I yet to fire it for over a year!!!


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## jks9199 (Oct 19, 2022)

Alan0354 said:


> I tried that first already, somehow, everywhere talked about everything else instead of just tell me what did they see when open up their knives. Like I said, I so wish people in Physics Forums are into knives so they know exactly what I am asking for.
> 
> My question is so simple, I just want to find anyone that open their knives can tell me if they see anyone that is what I want and give me the name and I'll go look it up. That's it, not asking for opinions or judgement. Just someone that see the inside. I have to explain what I am looking for, thereby all the pictures. It's not to justify whether I am right or wrong. Just describe what I am looking for.


If you're asking the same questions in different places, and getting the same answers in different places, maybe you should examine the point in common, and see if maybe your question isn't the problem....


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## Alan0354 (Oct 19, 2022)

jks9199 said:


> If you're asking the same questions in different places, and getting the same answers in different places, maybe you should examine the point in common, and see if maybe your question isn't the problem....


Maybe I should specify loud and clear in the first post I am not asking for opinion, just observation. BUT how many times since I tried to clarify this point?

If only I can edit after one hour, I would have done that to add to the first post.


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## Rich Parsons (Oct 19, 2022)

Alan0354 said:


> I have been trying to clarify, I am *not asking *about what is important for the knife, that's subjective. I was very specific on one specific part of the the knife that I am concern with, *NOT *that it's the most important, it's just my *specific *question. I know different things are important to different people, but that's not this thread is about.
> 
> Of cause you can see the video on testing the knives, a few broke the tip of the blade, the shape of the blade is important, BUT that's not the question of this thread. For that, I tend to choose Tanto shape that the tip becomes wider fast  as shown in the picture of my 3 knives.
> 
> ...



The Flipper style have issues as well. 
Balisong requires a couple of wrist movements. 
The others usually require a loose screw for where it gets tightened. 

I have used both, just does not fit my needs. 

The secondary and beyond motions take too long in a situation when a knife is required for self defense. 
And practice in a car the pull is not easy, yet not any harder than any other blade to clear and deploy . 

I also have an Emerson Trainer which not only allows for day to day practice, it allows you to roll with a knife and see if you can clear and deploy it. 


PS: I am not a fan of the FOX Karambit - just felt cheap and poorly made and as with 99.99% of all Karambits my hand aligns with the blade and my finger does not fit into the finger hole. 


As to the Wave requiring pants to hook, yes true for a single motion deploy and open. 
If pulled straight up it remains closed and can be handed to anyone asking you to clear your pockets. 
It also can be opened with the thumb, just not the HUGE thumb hole that some like spider co use.


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## Alan0354 (Oct 19, 2022)

Rich Parsons said:


> The Flipper style have issues as well.
> Balisong requires a couple of wrist movements.
> The others usually require a loose screw for where it gets tightened.
> 
> ...


The flipper I like is simple index finger tap like in the picture:





I cannot do well with the thumb hole type. This is a must for me to choose the knife. Too bad that rules out Cold Steel which I heard a lot of good things about. You can deploy very fast with the index finger tap, not like the balisong that needs to flip back and fore...........Also it's illegal in Kalifornia. I don't like FOX Karambit either, the look just doesn't appeal to me at all.

These are the few I am looking at:

https://www.amazon.com/gp/product/B09QBVJRY1/ref=ox_sc_saved_title_2?smid=A2X6NDN9Z5CRN7&psc=1

https://www.amazon.com/gp/product/B07QQF1TK6/ref=ox_sc_saved_image_3?smid=AVK2FQXQF9PPN&psc=1

https://www.amazon.com/gp/product/B08G9X4F45/ref=ox_sc_act_title_2?smid=ASLDWIKOQUN8O&psc=1


They are all Steel Will with no ball bearings. Do you know of other brands other than Cold Steel that doesn't use ball bearings in price range of $40 to $80? I don't want to get really cheap ones, they are the ones with no ball bearings, but then the material is too cheap. too bad Cold Steel are like the old Gerber that don't use index finger tap. I just not comfortable to use the thumb tap or the hole to open the knife.


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## Rich Parsons (Oct 20, 2022)

I do not at this time know who else uses the ball bearing.


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## Alan0354 (Oct 20, 2022)

Yeh, too bad, very few middle of the road knives don't use ball bearings, I understand the advantage of ball bearings. I join two other knife forums, no answer either except Hinderer that is so expensive and you can choose to have no ball bearings. It's in range of $400!!!

Too bad Cold Steel don't have the finger tap flipper.


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## JowGaWolf (Oct 20, 2022)

Dirty Dog said:


> Add Cold Steel to the list. They've got a reputation for solid work, and they're cheap, compared to the good stuff.


From The one knife I own to the reviews I've seen, Cold Steel does a good job.


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## frank raud (Nov 2, 2022)

In my limited experience with using a folding knife as a prybar, the knife breaks at the tip or the center of the blade. The knife is no doubt thinner at the pivot point, but I think you would have to have pretty sloppy tolerances for blade play to break the pivot point. As I understand physics, a pivot point stuffed with washers( ball bearing or otherwise) supported and reinforced by the knife frame and scales and a pivot screw will not be the weak point in the chain. Otherwise, tip breakage or even the blade breaking in half would not be the usual result of abusing the blade by applying lateral force.  But hey, none of us apparently know what we are talking about.


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## drop bear (Nov 2, 2022)

Alan0354 said:


> thanks, I just bought the second one of this, I cannot refuse when they are on sale for $24.
> https://www.amazon.com/gp/product/B09G2FNM5C/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
> 
> Here is the picture of my 3 favorite knives from big to small:
> ...


I read somewhere the cheaper steels might be stronger as well. Just hard to sharpen.


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## drop bear (Nov 2, 2022)

Alan0354 said:


> Yeh, too bad, very few middle of the road knives don't use ball bearings, I understand the advantage of ball bearings. I join two other knife forums, no answer either except Hinderer that is so expensive and you can choose to have no ball bearings. It's in range of $400!!!
> 
> Too bad Cold Steel don't have the finger tap flipper.



Kershaw?






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SpeedSafe, automatic, KVT. Take a look inside Kershaw pocketknife opening systems and to learn how each one makes your Kershaw easy to open and put to work.




					kershaw.kaiusa.com


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## Alan0354 (Nov 2, 2022)

frank raud said:


> In my limited experience with using a folding knife as a prybar, the knife breaks at the tip or the center of the blade. The knife is no doubt thinner at the pivot point, but I think you would have to have pretty sloppy tolerances for blade play to break the pivot point. As I understand physics, a pivot point stuffed with washers( ball bearing or otherwise) supported and reinforced by the knife frame and scales and a pivot screw will not be the weak point in the chain. Otherwise, tip breakage or even the blade breaking in half would not be the usual result of abusing the blade by applying lateral force.  But hey, none of us apparently know what we are talking about.


Yes, the tip of the knife is definitely the most critical where they usually break when prying. I just logically look at the whole knife and spot any potential weak point.

I buy knives with like tanto tips or blades with wide tip so they are stronger at the tip. I can control what I buy. The tricky part of the pivot point is you cannot see it until you open it. You cannot count on whether the knife is claimed to be tactical, survival or whatever, they might look sturdy outside:



But if you open it up, look at how thin that part is:




This is true for more expensive and known to be tough brands like OFF-GRID:




But look at the internal:




The blade pointed by GREEN arrow is good, BUT, look at the steel lining. They milled out the lining for the ball bearings and is paper thin on both linings, it's only 0.03" thick.

That's why I ask anyone open the knife, that's the only way to know.


this is the latest one I bought, no ball bearings:
https://www.amazon.com/gp/product/B09QBVJRY1/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

I open it, everything looks good.


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## Alan0354 (Nov 2, 2022)

drop bear said:


> I read somewhere the cheaper steels might be stronger as well. Just hard to sharpen.


Yes, that's why I don't buy expensive ones, max $70 so far.


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## drop bear (Nov 2, 2022)

Has anyone suggested a fixed blade yet? Which would solve the problem.


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## Alan0354 (Nov 2, 2022)

drop bear said:


> Has anyone suggested a fixed blade yet? Which would solve the problem.


It's illegal unless you open carry in Kalif. It's too big and eye catching carrying open.


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## frank raud (Nov 2, 2022)

Alan0354 said:


> Yes, the tip of the knife is definitely the most critical where they usually break when prying. I just logically look at the whole knife and spot any potential weak point.
> 
> I buy knives with like tanto tips or blades with wide tip so they are stronger at the tip. I can control what I buy. The tricky part of the pivot point is you cannot see it until you open it. You cannot count on whether the knife is claimed to be tactical, survival or whatever, they might look sturdy outside:


Have you ever had a blade break at the pivot point? Do you know anyone who has had their knife break at the pivot point?


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## Gerry Seymour (Nov 2, 2022)

Alan0354 said:


> Yes, the tip of the knife is definitely the most critical where they usually break when prying. I just logically look at the whole knife and spot any potential weak point.
> 
> I buy knives with like tanto tips or blades with wide tip so they are stronger at the tip. I can control what I buy. The tricky part of the pivot point is you cannot see it until you open it. You cannot count on whether the knife is claimed to be tactical, survival or whatever, they might look sturdy outside:
> View attachment 29232
> ...


It's worth noting that you're measuring the thinnest point, where that thinnest point isn't unaccompanied by thicker material. That's like judging a blade's potential strength by how thin the sharp edge is.

Then you have to factor in that the point you're looking at is supported to varying extents in every folding knife. The closer the tolerances (usually more expensive), the more supported that area of the knife will be.

So using this one measurement tells you almost nothing about the strength of that part of the knife, much whether that is the weak point you think it is. Physics, in this case, is far more complex than you're making it out to be.


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## Alan0354 (Nov 2, 2022)

Gerry Seymour said:


> It's worth noting that you're measuring the thinnest point, where that thinnest point isn't unaccompanied by thicker material. That's like judging a blade's potential strength by how thin the sharp edge is.
> 
> Then you have to factor in that the point you're looking at is supported to varying extents in every folding knife. The closer the tolerances (usually more expensive), the more supported that area of the knife will be.
> 
> So using this one measurement tells you almost nothing about the strength of that part of the knife, much whether that is the weak point you think it is. Physics, in this case, is far more complex than you're making it out to be.


True, but when it gets down to 0.03", that's thin. Remember, blade material is optimized for edge retention, meaning they sacrifice toughness. In another word, it tends to be brittle. When getting down to this thin, cracking is more a concern to me upon applying force. Any knife that is $70 or under are made in China. I hate to say being a Chinese, THEY ARE SLOPPY!!! You really trust the consistency of their quenching of the blades? Error in this can make the blade brittle if it is thin.

Also, what you said holds more truth if they use a flat washer where the pressure is applied evenly over the large surface. But with ball bearing, all the pressure are on the tip of those little balls, meaning most of the thin part is NOT being supported.

True, I search on youtube on torturing of knives using it to pry. I have NOT seen it break at the pivot point. BUT, upon checking each knife they use, majority of them don't have ball bearings.

Also, NOT all the ones with ball bearings are thin at that point, I have *3 knives already that are at least 0.05" to 0.07"*. Anything above 0.05", I totally agree the rest of the structure at the pivot point will strengthen it up and won't be the weakest link of the knife.


To follow up with the sloppy workmanship from China, My favorite knife is this one:
https://www.amazon.com/dp/B09G2FNM5C?ref=ppx_yo2ov_dt_b_product_details&th=1

I bought 5 and return 1, I measure that part. one is 0.06", two are 0.05", one is 0.04" which I return. I just got another one today that measure 0.047". I am still thinking whether I want to return it or not!!! How can they be so sloppy in making them? The space is very critical it that area. Too thick, the knife binds if you tighten the screw. Too thin, you have slop.

Pivot screw of 80% of knives I bought ( over 10 of different brands) CANNOT be tighten or else the blade will bind or even stuck. they use Lock Tight stuff to glue the screw without tightening it. That's how sloppy they are. Most of them I can thin out the non-metal( they call G10 material) outer cover at the pivot screw area so I can tighten the screw without problem!!!

I am born cheap, I am not willing to pay over $80 for a pocket knife. So I have to worry about all the stupid things!!!


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## Alan0354 (Nov 2, 2022)

This is my 2 most favorite knives:




I just got the top one yesterday, it's Steel Will Warbot. The lower one is the Laurisilva medium size with ball bearings but 0.05" thick at the critical part. The Warbot is hefty. Look at the internal picture, everything is thick:


 It uses bronze washers instead of ball bearings. I can still open with a flick of the index finger, not quite as smooth as those with ball bearings. The blade is 0.16" thick, it's thick. Look at the blade tip, it's not going to snap as easy. The two steel liners are 0.06", that's thick!!!!

I already bought a second one as back up because they raise the price right after I bought it, I paid $70. I manage to get the second one for the same price. So what the hack. I think I am good for a while now.


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## Gerry Seymour (Nov 2, 2022)

Alan0354 said:


> True, but when it gets down to 0.03", that's thin. Remember, blade material is optimized for edge retention, meaning they sacrifice toughness. In another word, it tends to be brittle. When getting down to this thin, cracking is more a concern to me upon applying force. Any knife that is $70 or under are made in China. I hate to say being a Chinese, THEY ARE SLOPPY!!! You really trust the consistency of their quenching of the blades? Error in this can make the blade brittle if it is thin.
> 
> Also, what you said holds more truth if they use a flat washer where the pressure is applied evenly over the large surface. But with ball bearing, all the pressure are on the tip of those little balls, meaning most of the thin part is NOT being supported.
> 
> ...


Most of the area isn’t that thin. You’ve focused on the weakest-sounding part, but a part that is backed by thicker metal around it, and both are braced to varying extents by other components.

In one design (the one with the thinnest measurement) you appear to be judging based on a small flange of thin metal inside the main bod of metal. That isn’t a structural member in that situation.


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## Alan0354 (Nov 2, 2022)

Gerry Seymour said:


> Most of the area isn’t that thin. You’ve focused on the weakest-sounding part, but a part that is backed by thicker metal around it, and both are braced to varying extents by other components.
> 
> In one design (the one with the thinnest measurement) you appear to be judging based on a small flange of thin metal inside the main bod of metal. That isn’t a structural member in that situation.


Maybe. I did think about it, the surrounding is all thick, just the center close to the hole that is thin. Maybe you are right.

I can tell you A LOT of knives disassembly videos show that part  is thin( without measuring, seemed like 0.04" or under). This including most of the Kubey 3" or longer folding knives. A lot of Bestech knives also. Maybe there is truth of what you said. 

I am NOT a mechanical engineer, I only can look at the obvious things that it's thin. Also, I think I found what I want already. One of my favorite one is at least 0.05" and the other don't even have bearings. So I am good for now.

It's funny I posted the same post in two knife forums, those people don't know jack and just came back and said go buy a more expensive knife!!! Nobody really stop and at least question and talk about my finding whether they agree or not. 

Never thought you actually comment base on my finding and say something I have to stop and think and *maybe *it's valid in more engineering point of view.......In a MARTIAL ART FORUM!!! At least a lot of knives seems to agree with you.

Anyway, I am not a knife enthusiast, it's all for self defense and I want as strong knife like I chose the fiber filled nylon cane for stick fight instead of any wood cane. The knife is only the last line of defense if heaven forbid I lose my cane in the fight. Now it's more important for me to Practice using a knife like I practice stick fight with the cane.


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## Gerry Seymour (Nov 3, 2022)

Alan0354 said:


> Maybe. I did think about it, the surrounding is all thick, just the center close to the hole that is thin. Maybe you are right.
> 
> I can tell you A LOT of knives disassembly videos show that part  is thin( without measuring, seemed like 0.04" or under). This including most of the Kubey 3" or longer folding knives. A lot of Bestech knives also. Maybe there is truth of what you said.
> 
> ...


My wife has a master’s in mechanical engineering, so I’ve learned to pay attention to some of this.


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## wab25 (Nov 3, 2022)

Alan0354 said:


> I am born cheap, I am not willing to pay over $80 for a pocket knife. So I have to worry about all the stupid things!!!


Interesting...

On this page (page 3) alone, you have spend $240 on knives....


Alan0354 said:


> To follow up with the sloppy workmanship from China, My favorite knife is this one:
> https://www.amazon.com/dp/B09G2FNM5C?ref=ppx_yo2ov_dt_b_product_details&th=1
> 
> I bought 5 and return 1


4 at $25 each....



Alan0354 said:


> I already bought a second one as back up because they raise the price right after I bought it, I paid $70. I manage to get the second one for the same price


2 at $70 each

Thats $240 total.... And you reference 3 other knives you have purchased.... all on this page.... You could have just bought one of the nicer more expensive knives... and probably saved money.

All this time and money, investigating a point that you feel is weak.... when neither you, nor I, nor anyone else here... could find a single instance of failure, at that point, in your use case. If you had even one example of a failure at that point, it may be worth looking at....

But, hey, its your time and your money....


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## tkdroamer (Nov 3, 2022)

Gerry Seymour said:


> My wife has a master’s in mechanical engineering, so I’ve learned to pay attention to some of this.


Cool. I have an engineering background.


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## Alan0354 (Nov 3, 2022)

Gerry Seymour said:


> My wife has a master’s in mechanical engineering, so I’ve learned to pay attention to some of this.


OK, this is just talking only about theory.   This is what I drew out:






A)  I was thinking about what you said. I would agree with you if the support is a FLAT WASHER as shown in Fig. 1. You can see the whole thin section of the blade(*RED*) is supported by the flat washer (*GREEN*). Even the blade is thin at that point, it is still very well supported.

B) But look at Fig.2.  If it is supported by ball bearings as show in (*GREEN*) balls. The pressure right a the tip of the ball bearings pointed by (*RED*) arrow. You see, there is NO SUPPORT in the rest of the area that is very thin. This will not give good support and the pressure is on the thin part of the blade.

See what do you think.


I have to agree, there doesn't seems to be an issue in real life. There is enough knives that has very thin part in that area. It would be better known if it is a common problem. maybe people don't use the knife for prying and all purpose. But to me, I want it to be all-in-one that if heaven forbid I have to cut myself out of a car accident, I might have to pry metal to get out and that's ALL I HAVE. That's why I am not even looking for the best steel blade that has best edge retention, just have to survive one time, but it has to be tough enough to survive that ONE TIME!!!

I think I found my knife already, just talking out of curiosity.




As for argument about putting a pry bar in the glove box, what if I am driving, I cannot reach it. Worst is if I am a passenger at the back seat?!!! It has to be ON ME all the time.


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## frank raud (Nov 3, 2022)

Alan0354 said:


> Just think about, the blade is at least 0.11" thick solid, the handle has TWO metal sides each of 0.06" thick sandwiching the blade. You don't need to be an engineer to tell where is the weak point!!! Just common sense.


Can you point to ONE example of a blade breaking at the pivot point?  Can you find an example of the tip breaking on a knife, or a blade breaking in half? Where's the weak point? It's just common sense.


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## drop bear (Nov 3, 2022)

Here is the cold steel sr1. One of their cheaper tank knives. 

Not sure how much you want a folder to take. But it takes a bit.


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## Alan0354 (Nov 3, 2022)

drop bear said:


> Here is the cold steel sr1. One of their cheaper tank knives.
> 
> Not sure how much you want a folder to take. But it takes a bit.


Cold Steel has good knives, my problem is for the life of me, I cannot flip open those knives with thumb tap like this one!! I need the flipper tap on the other side that is flipped by the index finger. I have one knife with thumb tap and I practiced on it, I almost cut myself trying to flip it open.

If I can flip with the thumb, believe me, Cold Steel would be on my list. There are other brands like Gerber and SOG that have thumb tap and they have some good ones too.

This is a video that disassemble the SR1:





Notice it doesn't use ball bearings? A lot of Cold Steel knives don't use ball bearings, so are some other brands that are known for the ruggedness. Like Cold Steel AD10 also. Here are some disassemble videos of Cold Steels that don't use ball bearings:















There MUST be good reason why the ones that are famous for their ruggedness don't use ball bearings.

I went through A LOT of knives disassembly videos AND a lot of pocket knives torturing videos. A lot of the torture videos are on knives without ball bearings. That gives a deceptive impression that the pivot point is not a weak point. That is because a lot of the knives they tortured did not have ball bearings.


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## Alan0354 (Nov 3, 2022)

This is the Steel Will Warbot I bought already. This is MY disassembly picture:




This is a very new knife that just came out early this year, there's no video for it. Just look at the thickness of everything and using bronze washere instead of ball bearings. I bet this one can do very well in torture test also.

The liner is solid 0.06" thick cover the whole inside of the knife. Blade is 0.16" thick with wide tip. One thing, it's quite heavy.

I just bought another Steel Will, the Cutjack:

This is the disassemble video:





Also no ball bearings. The Warbot is smooth enough to flip it open with just the index finger hopefully this one too. There's no reason why not.


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## Alan0354 (Nov 4, 2022)

I put in different post to avoid making it too long. There's another very important feature of a knife I got to have, it's the long extension at the front of the handle like my two knives:




You see the long extension at the bottom front of the handle(pointed by the *RED* arrow) that is formed by the flipper tap of the blade. This is very important to protect the hand from the knife being shoved back into the hand when thrusting(shanking). I don't know why people don't stress on this. It would be a disaster if the blade got shoved back into the hand. there goes the tendons!!!

I practice shanking on the heavy bag with a plastic knife, it definitely want to push back into my hand. I don't know why people buy knives that doesn't have or very little of this to protect the hand. That's the other reason I like knives with flipper tap like this.


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## Alan0354 (Nov 4, 2022)

This kind of knife is very popular, I would not want to touch this with a 10' pole!!!




There is no protection of the knife from being shoved back into the hand when thrusting. You thrust, hit a bone and you'd be in deep trouble.

You can see the ones I picked all with long flipper tap, much longer than average. That's why, all in all, it's not easy for me to find a knife.


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## Monkey Turned Wolf (Nov 4, 2022)

Alan0354 said:


> You thrust, hit a bone and you'd be in deep trouble.


What exactly would be the trouble if you hit a bone? 

Also, where are you hitting that you would hit a bone? From my experience, FMA teach the idea that you slash (so no option to thrust into bone) pretty much everywhere but ribs, neck and eyes. My experience with native american knife fighting is the same. So what exactly is your goal here that involves thrusting into the bone and causing an issue?

My assumption would be that you're thrusting when you should be slashing/not properly trained with a knife, but I'm open to accepting different styles teaching something differently to how I've learned it.


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## Alan0354 (Nov 4, 2022)

Monkey Turned Wolf said:


> What exactly would be the trouble if you hit a bone?
> 
> Also, where are you hitting that you would hit a bone? From my experience, FMA teach the idea that you slash (so no option to thrust into bone) pretty much everywhere but ribs, neck and eyes. My experience with native american knife fighting is the same. So what exactly is your goal here that involves thrusting into the bone and causing an issue?
> 
> My assumption would be that you're thrusting when you should be slashing/not properly trained with a knife, but I'm open to accepting different styles teaching something differently to how I've learned it.


I am just saying. I have only been practicing for 2 weeks more seriously, I practice thrusting to the belly and the head, I guess the head has bones. Even aiming for the eye, there's still bone at the back of the eye. Or even the neck, it's very bony. 

With the knives I chose, they will mitigate this issue. At least it's not a problem thrusting on the heavy bag.


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## Monkey Turned Wolf (Nov 4, 2022)

Alan0354 said:


> I am just saying. I have only been practicing for 2 weeks more seriously, I practice thrusting to the belly and the head, I guess the head has bones. Even aiming for the eye, there's still bone at the back of the eye. Or even the neck, it's very bony.
> 
> With the knives I chose, they will mitigate this issue. At least it's not a problem thrusting on the heavy bag.


A heavy bag is different than a person. Re: the head. If you are targeting a soft area, use a thrust. If a hard area, slash. Doesn't matter what type of knife it is, that's pretty much universal. And if stabbing the eye and you get far enough to stab the bone at the end, you can withdraw it. Ideally before you hit that-there's plenty of squishy stuff first to hit then withdraw. 

With the neck I agree it's bony. Typically try slashing it. But there are certain areas you can thrust in the neck, effectively. Which is most of the neck honestly, and again if you're not confident, just slash the neck/arteries.


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## drop bear (Nov 4, 2022)

The ti lite is a flipper.


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## Gyakuto (Nov 4, 2022)

You get what you pay for! A folding knife at $40-70 is probably not going to be very robust. I buy folding knives from Italian craftsmen (they seem to be excellent) and would not pay less than £150 ($170, an arbitrary figure but seems to be a good minimum point). But generally, fixed blades are my preference. Big ones!😈


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## tkdroamer (Nov 4, 2022)

Alan0354 said:


> OK, this is just talking only about theory.   This is what I drew out:
> 
> View attachment 29247
> 
> ...


Ball bearings do not work that way. They distribute the load unilaterally across all the balls, inside a race that is the opposing shape. It is a more precision point of contact versus a flat washer. Effectively, the bearing carries the load and perpendicular forces, not the shaft or, in this case blade hole.


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## Gerry Seymour (Nov 4, 2022)

tkdroamer said:


> Cool. I have an engineering background.


A far more useful and versatile background than many give it credit for.


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## Dirty Dog (Nov 4, 2022)

Gerry Seymour said:


> A far more useful and versatile background than many give it credit for.


As always, that depends. I doubt a background in, say, biomolecular engineering would help much in this discussion...


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## Gerry Seymour (Nov 4, 2022)

Dirty Dog said:


> As always, that depends. I doubt a background in, say, biomolecular engineering would help much in this discussion...


Certainly. I was more talking about the problem-solving and analysis engineering education seems to focus on. It’s useful well beyond the scope of their discipline.


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## tkdroamer (Nov 4, 2022)

Gerry Seymour said:


> A far more useful and versatile background than many give it credit for.


I was lucky to know what I wanted to do when I was 15 years old. I have a Masters in EE and engineering management, but a lot of my work is around machine building, so I do a lot of ME type stuff.


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## Alan0354 (Nov 4, 2022)

tkdroamer said:


> I was lucky to know what I wanted to do when I was 15 years old. I have a Masters in EE and engineering management, but a lot of my work is around machine building, so I do a lot of ME type stuff.


I too found my ultimate passion in EE. I was a musician until I was 25, my degree was BioChemistry. Then I found my ultimate passion in electronics. I started from the bottom, promoted to EE, became manager of EE before I retired. Since retirement, I still study and worked on electronics at home. I went back to music electronics designing guitar amps and extreme high end hifi power amps.

I am very involved in mechanical design also because the kind of instruments we design, the mechanical design is every bit affecting the electronics design about the placement, location of all the stuffs.

I find no education, theory is good enough unless one has a good dose of common sense with I found a lot of people don't have even with high education. When I hire engineers or techncians, I really don't put too much in what school they came from or even what experience they had. I gave them a test I made up, mostly simple stuffs that you can do it if you have a good dose of common sense and truly understand the stuffs. In the analog part test, a lot is straight from a book I studied in the first class of analog circuit in a technical school called Heald College. Those are for technicians. You would think and EE should be able to answer that.............WRONG!!! Anyone failed the test, I just cut the interview short and sent them away politely.

My most favorite part of electronics is RF/microwave and electromagnetics. That I can see and predict how the signal move and all that. Even after I retired in 2005, I still spent a few years studying electrromagnetics and antenna until I realize I memory is really going down, that I forget stuffs I studied. I kept very good notes, a lot of times I read back my notes I wrote a few weeks ago, it's like I never seen it before. But then after I follow my notes step by step, I realized I really UNDERSTOOD it!!! And it's like I have no memory of it anymore!!!! It's a scary feeling. I kind of stop studying since and just more to design amplifiers which was what got me into electronics and quit playing music.

Funny the company I worked for before called me back in 2015 to design the next phase of the instrument and I worked as a contractor for a year and half before I really call it a quit. The tax was really bad and because of my income, it hurts my wife's medicare payment, not only paying a lot of tax, it increased the medicare payment!!!! So I really retired since as my wife really want me to quit.


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## Alan0354 (Nov 4, 2022)

tkdroamer said:


> Ball bearings do not work that way. *They distribute the load unilaterally across all the balls*, inside a race that is the opposing shape. It is a more precision point of contact versus a flat washer. Effectively, the bearing carries the load and perpendicular forces, not the shaft or, in this case blade hole.


Ball bearings are not the weak link here, We are talking about the thin flat part of the blade that is the weak part. Look at Fig.2 of post #61, The balls only contact to the surface of the metal at a PIN POINT as indicate. The pressure is at a pin point where the ball contact the flat surface, there is no support on the surrounding surface. It is very different from the case drawn in Fig.1 with a flat washer where the force is distribute evenly on the surface of the thin part....which is surrounded by the thick part of the blade.


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## tkdroamer (Nov 5, 2022)

Alan0354 said:


> Ball bearings are not the weak link here, We are talking about the thin flat part of the blade that is the weak part. Look at Fig.2 of post #61, The balls only contact to the surface of the metal at a PIN POINT as indicate. The pressure is at a pin point where the ball contact the flat surface, there is no support on the surrounding surface. It is very different from the case drawn in Fig.1 with a flat washer where the force is distribute evenly on the surface of the thin part....which is surrounded by the thick part of the blade.


I have followed the thread. Yes, disassembled there is a thin cross section. But assembled, it is carrying little to none of the load. You don't seem to understand engineered design.
Yes, there could be issues if the knife assembly were to somehow get loose causing undue loading on the thin cross section.



Alan0354 said:


> Ball bearings are not the weak link here, We are talking about the thin flat part of the blade that is the weak part. Look at Fig.2 of post #61, The balls only contact to the surface of the metal at a PIN POINT as indicate. The pressure is at a pin point where the ball contact the flat surface, there is no support on the surrounding surface. It is very different from the case drawn in Fig.1 with a flat washer where the force is distribute evenly on the surface of the thin part....which is surrounded by the thick part of the blade.


I have followed the thread. 
Yes, disassembled there is a thin cross section. But assembled, little to none of the load would be on the hole section. You do not seem to understand engineered design. 
Yes, if the knife assembly were to somehow get loose, it could load the hole's cross section. But that would be akin to operator error wouldn't it?


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## tkdroamer (Nov 5, 2022)

Alan0354 said:


> I too found my ultimate passion in EE. I was a musician until I was 25, my degree was BioChemistry. Then I found my ultimate passion in electronics. I started from the bottom, promoted to EE, became manager of EE before I retired. Since retirement, I still study and worked on electronics at home. I went back to music electronics designing guitar amps and extreme high end hifi power amps.
> 
> I am very involved in mechanical design also because the kind of instruments we design, the mechanical design is every bit affecting the electronics design about the placement, location of all the stuffs.
> 
> ...


Nice. 
To be clear my EE is electrical engineer, not electronics. I know they are associated but an EE degree can go in many directions much like an ME. I gravitated into control & automation. 
Way back in the day one place I worked at had a ton of Seimen's controllers and I/O. We had a steady load of board level repairs that we could do ourselves. When Seimen's came out with the next generation of hardware, the boards were so compact we could no longer do repairs ourselves, effectively making the I/O cards throw away units.


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## Rich Parsons (Nov 5, 2022)

Dirty Dog said:


> As always, that depends. I doubt a background in, say, biomolecular engineering would help much in this discussion...





Gerry Seymour said:


> Certainly. I was more talking about the problem-solving and analysis engineering education seems to focus on. It’s useful well beyond the scope of their discipline.



Yes, a good engineer that learns in college about systems and how the parts make something complete or larger parts, and how they connect can have discussions in lots of areas by asking the right questions. 

If they only think about the specific minimized project then no they will not be able to join the conversation productively.


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## Alan0354 (Nov 5, 2022)

tkdroamer said:


> I have followed the thread. Yes, disassembled there is a thin cross section. But assembled, it is carrying little to none of the load. You don't seem to understand engineered design.
> Yes, there could be issues if the knife assembly were to somehow get loose causing undue loading on the thin cross section.
> 
> 
> ...


I disagree, the ball bearings make it a pin point pressure on the thin part BUT there is no support right next to the pressure point where there are NO thick part of the blade to hold it together. Below is the example.





Both cases, we apply the same weight onto a thin plank, but the top one apply evenly along the plank.  In the lower drawing, the pressure is only in the middle, there is no support next to it, it's a long distance from the pressure point to the support on each side. Which one you think it will hold up better?

Please do NOT assume I don't know engineering. I have been EE and manager of EE for 30 years and deeply involved in mechanical design. I own 3 US patents and published 2 papers in American Institute of Physics, Review of Scientific Instruments solely on my idea and I got the phase II SBIR funding on the idea of the second paper.

I worked for Seimens Medical division designing the front end of their first generation Ultra Sound medical scanner with color doppler from 1985 to 1988. I don't like Seimens, too stuffy and slow. I like small starter companies where I do everything.

We all called EE, electronics or electrical.


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## Alan0354 (Nov 5, 2022)

OK, let me try another way to describe more closely. This is to ASSUME that there is no slack and the circle of ball bearings apply pressure evenly around the whole circle.




I drew the blade with the milled out thin part and the hole in the middle for the pivot screw. I drew the path of the *BALL BEARINGS* in *RED*.

On the top drawing, it's typical of the ball bearings that the path is about mid-way between the edge of the *pivot hole* and the junction where the blade goes back to the *THICK* part.

I labelled in *GREEN* the critical distance. If the distance is large, the thick part of the blade is* NOT going to help the thin part* where the path of the ball bearings run.

On the LOWER drawing, IF the path of ball bearings is *closer *to the edge where the thin part transition to thick part. Then you can count on the *thick part can help strengthen* it as the path of the ball bearings are very close to the thick part of the blade.


Now, this is assume like what you said that there is NO SLACK and all the balls are in contact. If there is any slack, it becomes a pin point pressure and that will be bad.

Every knife I open that with ball bearings, they are all like the TOP drawing.


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## Gerry Seymour (Nov 6, 2022)

Alan0354 said:


> OK, this is just talking only about theory.   This is what I drew out:
> 
> View attachment 29247
> 
> ...


So a couple of thoughts on this.

Firstly, I suspect (but do not know) two reasons why more expensive/robust knives tend not to use ball bearings. 1) ball bearings present an additional potential point of failure. 2) that can be mitigated by using tight tolerances and better surfaces with a washer, which is more expensive. Others with better understanding of materials might be able to point out if/where I'm mistaken in this.

Secondly, you're still looking at a cross-section as if it were the entire structure. There is a small area that is thinner than the rest, and how it is supported. Since that thin area is such a small portion of the structure, what you should be looking at is how the section around it is supported. Again, the materials attached to it likely add structure, and are adding it to the stronger portion (where it can do more good than it can at that thinnest bit).

Here's an analogy for the way I'm looking at this. Look at your car door. What's the weakest bit? Probably that glass. If you assessed the door's ability to withstand a side impact based upon the weakest bit, you'd miss the structure, entirely. The majority of the door is sheet metal (or less), but there's also a beam inside the door that braces against structural members when closed. So in assessing the door for this, you should ignore the glass and focus on what will be bearing that load: the side-impact beam and how it braces.


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## tkdroamer (Nov 6, 2022)

Alan0354 said:


> Ball bearings are not the weak link here, We are talking about the thin flat part of the blade that is the weak part. Look at Fig.2 of post #61, The balls only contact to the surface of the metal at a PIN POINT as indicate. The pressure is at a pin point where the ball contact the flat surface, there is no support on the surrounding surface. It is very different from the case drawn in Fig.1 with a flat washer where the force is distribute evenly on the surface of the thin part....which is surrounded by the thick part of the blade.


If that is the case, it would be a Thrust bearing, not a case bearing. But the effects are the same. IF the knife is assembled correctly, the load is distributed across all the ball bearings, not just two points of contact like post #61 shows. 
For certain, a thrust washer can handle more direct load, but it is a huge tradeoff when the part has to move frequently. The drag coefficient of a thrust washer is very high.


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## tkdroamer (Nov 6, 2022)

Alan0354 said:


> OK, let me try another way to describe more closely. This is to ASSUME that there is no slack and the circle of ball bearings apply pressure evenly around the whole circle.
> View attachment 29262
> 
> I drew the blade with the milled out thin part and the hole in the middle for the pivot screw. I drew the path of the *BALL BEARINGS* in *RED*.
> ...


You are making my point about the knife being properly assembled. Remember, all bearing surfaces, whether bearings or washers are used, have to be flat and parallel. So, the thick part/thin part you mention would have to be machined to the same thickness, wouldn't it?


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## tkdroamer (Nov 6, 2022)

Alan0354 said:


> I disagree, the ball bearings make it a pin point pressure on the thin part BUT there is no support right next to the pressure point where there are NO thick part of the blade to hold it together. Below is the example.
> 
> View attachment 29261
> Both cases, we apply the same weight onto a thin plank, but the top one apply evenly along the plank.  In the lower drawing, the pressure is only in the middle, there is no support next to it, it's a long distance from the pressure point to the support on each side. Which one you think it will hold up better?
> ...


You are describing spanning and distributed weight.  This has zero to do with the knife.


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## Rich Parsons (Nov 6, 2022)

Alan,

I get where you trying to go with your discussion. 
I have seen this for transmissions and does one use a ball bearing , a cylinder bearing, or ... 
Each has advantages, from cost and serviceability, and functionality to address the loads. 

What I would like to understand is what load / force are you trying argue is the issue for a specific design?
Once I understand this then I can comment on the design quality from my limited experience.


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## Dirty Dog (Nov 6, 2022)

Rich Parsons said:


> Yes, a good engineer that learns in college about systems and how the parts make something complete or larger parts, and how they connect can have discussions in lots of areas by asking the right questions.


That's not a feature of being an engineer. It's a feature of being educated.


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## Rich Parsons (Nov 6, 2022)

Dirty Dog said:


> That's not a feature of being an engineer. It's a feature of being educated.


I was speaking of Good Engineers. 
Because some / many I know cannot see the forest for the trees, nor the cliff past the existing tree.  

And yes a good education can bring the idea of a system. I did not mean to imply at all that it was limited to any one area of study


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## Alan0354 (Nov 6, 2022)

Gerry Seymour said:


> So a couple of thoughts on this.
> 
> Firstly, I suspect (but do not know) two reasons why more expensive/robust knives tend not to use ball bearings. 1) ball bearings present an additional potential point of failure. 2) that can be mitigated by using tight tolerances and better surfaces with a washer, which is more expensive. Others with better understanding of materials might be able to point out if/where I'm mistaken in this.
> 
> ...


This is completely different. The glass can be broken on the car door, but the metal still keep the passenger safe. The metal of the door can collapse, but as long as it is still serve as a barrier between the passenger and the outside, it still serve it's purpose.


THIS is very DIFFERENT from the folding knife. If the thin part crack, YES, the blade is still going to be held in place by the pivot screw onto the handle. BUT it will wobble. If you look at the structure of the folding knife, the blade is held open by a* THIN* frame(in frame lock) or a small hook. If the blade start flopping, it likely will not be held secure. The next time you thrust, the* blade might collapse onto the fingers.............EVEN though it still held together in one piece*.

You have to look at the situation. It is very critical the blade do* NOT* have free play and wobble EVEN THOUGHT it is held together no matter what. Those folding knife has to be more precision than people give them credit. That's one thing I have to work on a lot of the knives to make sure the line lock moves deeper under the blade. A lot of them came with the liner only like half way under the blade, any shock might make the liner slip and let the blade collapse onto the hand of the user. It's very critical. You cannot allow the blade to be wobble at all>


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## Alan0354 (Nov 6, 2022)

tkdroamer said:


> You are making my point about the knife being properly assembled. Remember, all bearing surfaces, whether bearings or washers are used, have to be flat and parallel. So, the thick part/thin part you mention would have to be machined to the same thickness, wouldn't it?


No.
This example is ASSUMING it is properly assembled and the circle of bearings are pressing on the red circle evenly.

Still it depends on the CRITICAL distance indicated by the GREEN. If it is farther away, the thick part doesn't help as much.


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## Alan0354 (Nov 6, 2022)

Dirty Dog said:


> That's not a feature of being an engineer. It's a feature of being educated.


From my experience, good engineer must have a good dose of COMMON SENSE and a good INSTINCT. Ability to think out of the box, open to other's ideas and think about it. Never dismiss other people ideas.

Saw many engineers that never get out of the books and theories, that they never can move on and adapt to the real world. I worked with a software engineer from UC Berkley and a ME from Stanford. If I were their manager, I'll FIRED both of them first day. they only know how to talk theory, why this doesn't work, why that doesn't work. I DON'T care why it doesn't work, give me something that works!!!

I was working for 10 years in an environment 50% were PhDs. Nobody ask people what degree and all that. We only care whether it works or not.


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## Gerry Seymour (Nov 6, 2022)

tkdroamer said:


> If that is the case, it would be a Thrust bearing, not a case bearing. But the effects are the same. IF the knife is assembled correctly, the load is distributed across all the ball bearings, not just two points of contact like post #61 shows.
> For certain, a thrust washer can handle more direct load, but it is a huge tradeoff when the part has to move frequently. The drag coefficient of a thrust washer is very high.


Out of curiosity, would you be able to keep the connection tighter (more force holding it closed) with a bearing than a washer? I'd assume the rolling ball would move much more readily under those conditions than a flat washer. And if that's true, would the difference in force need to be significant?

I'm having trouble picturing all the moving parts of this.


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## Gerry Seymour (Nov 6, 2022)

Dirty Dog said:


> That's not a feature of being an engineer. It's a feature of being educated.


I think it's part of what's needed in certain curricula (engineering being a great example) just to survive. While liberal arts educations can give a great path to basic logic, there's not much problem-solving focus in most degree programs.


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## Gerry Seymour (Nov 6, 2022)

Alan0354 said:


> This is completely different. The glass can be broken on the car door, but the metal still keep the passenger safe. The metal of the door can collapse, but as long as it is still serve as a barrier between the passenger and the outside, it still serve it's purpose.
> 
> 
> THIS is very DIFFERENT from the folding knife. If the thin part crack, YES, the blade is still going to be held in place by the pivot screw onto the handle. BUT it will wobble. If you look at the structure of the folding knife, the blade is held open by a* THIN* frame(in frame lock) or a small hook. If the blade start flopping, it likely will not be held secure. The next time you thrust, the* blade might collapse onto the fingers.............EVEN though it still held together in one piece*.
> ...


It's only different because you're looking at what happens if it fails. Look, instead, at whether it's important to the structure under the load in question. You could replace the glass with 1/4" steel, and it wouldn't make that much difference in most side-impact crashes, as far as what happens to the structure of the door.

Analogously, it's also possible that replacing the thin section with something 3x as thick would have little impact on the overall structure of the knife.


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## Alan0354 (Nov 6, 2022)

Gerry Seymour said:


> It's only different because you're looking at what happens if it fails. Look, instead, at whether it's important to the structure under the load in question. You could replace the glass with 1/4" steel, and it wouldn't make that much difference in most side-impact crashes, as far as what happens to the structure of the door.
> 
> Analogously, it's also possible that replacing the thin section with something 3x as thick would have little impact on the overall structure of the knife.


As I said, it's different. This is a picture of the typical knife with ball bearings.





Let's try this way. Look at the picture. This is a typical knife with ball bearings. You can see the DAYLIGHT between the frame on both sides to the blade. The only part that hold the blade tight is the two ball bearings (labeled *BB*) on each side of the blade. There is *NOTHING* else supporting the blade. It is only until the thin part *CRACKS *then the blade can lean on the side plates of the handle to get support.

I have an arrow pointing at the frame lock. In the picture, I worked on it so it goes way under the blade as shown. A lot of knives are not as good, some engage only like 1/2 way. If the blade starts wobbling after it's broken, it might disengage from the frame lock and collapse onto the hand. This is NOT as forgiving as the car door in your example.

As I said, there are knives that made the critical part thicker, it doesn't take a scientist to do that. I have a few knives that has 0.05" or thicker on that part. It's just pure negligence or stupidity they have that part so thin.



EDIT: If you look at the frame lock part of the knife, it has to be quite precise. Notice the bottom of the blade where it touches the frame lock, it is SLANTED. It only works if everything is quite precise and no slack. If the blade start wobbling, it might create a gap in between the blade and the frame lock, the blade can be freed up to close onto the person's hand. It's NOT very forgiving.


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## Alan0354 (Nov 6, 2022)

Let me show another picture of the knife that actually has very thin part, the Sencut Acumen. The thickness is only 0.03". Look at the gap between the side and the blade on both sides are WIDER than the one in the last post. 




Look at it, there is NOT SUPPORT of the blade other than the ball bearings on both sides.....until it cracks. Also, notice the frame lock metal is NOT as thick as the other one, it can easily slip if the blade start to wobble.


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## tkdroamer (Nov 6, 2022)

Gerry Seymour said:


> Out of curiosity, would you be able to keep the connection tighter (more force holding it closed) with a bearing than a washer? I'd assume the rolling ball would move much more readily under those conditions than a flat washer. And if that's true, would the difference in force need to be significant?
> 
> I'm having trouble picturing all the moving parts of this.


A bearing will move more freely under the load a knife would typically see, assuming as you say the connection or assembly is correct. 
The heaviest recording moving (not rolling) loads are on thrust bearings (flat bearings, aka washers).
It is amazing the variation in bearing quality. Two bearings can have the exact same numbers stamped on them and the life cycle and load they can handle be very different.


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## Alan0354 (Nov 6, 2022)

What is a thrust bearings? I only know roller bearings which looks like a cylinder or just ball bearings that is a round ball.


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## tkdroamer (Nov 6, 2022)

Alan0354 said:


> As I said, it's different. This is a picture of the typical knife with ball bearings.
> 
> View attachment 29263
> 
> ...


That is more the open design of the knife than anything else. Most knives cover up much of the area in your photo. More importantly, look how big the bearing cross section is. That is what is carrying the load. It is Huge compared to the center hole. 

Of course, it is the thin section that cracks. This will be consistently true unless there is a bad area in the steel. The same thing is true even if it was on thrust washers. There has to be some clearance.


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## Alan0354 (Nov 6, 2022)

tkdroamer said:


> That is more the open design of the knife than anything else. Most knives cover up much of the area in your photo. More importantly, look how big the bearing cross section is. That is what is carrying the load. It is Huge compared to the center hole.
> 
> Of course, it is the thin section that cracks. This will be consistently true unless there is a bad area in the steel. The same thing is true even if it was on thrust washers. There has to be some clearance.


I don't know what is "open" design. I can assure you MOST if not ALL folding knives look like that. I have more than 10 myself from different brands, this is a good representative of how it looks.

The bearings diameter is NOT a lot bigger than the center hole.





This is the picture of Sencut Acumen, you can clearly see the diameter of the ball bearings vs the center hole. In fact, you can see the ball bearing track mark on the black blade. All the ball bearings I saw look very similar, I can show you more pictures of other brand if you want.

I really don't follow what you said, I don't think we are talking on the same page.


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## Alan0354 (Nov 6, 2022)

Guys, this is NOT something I discover, They know about it. There are few that are thick in that part. Here are the pictures of 3 of mine that are thick:

Off-Grid Baby Rhino with thickness of *0.073"*:





Kubey Dugo KU159 with thickness of *0.063"*:




This is Laurisilva with thickness of *0.053"*:





This is NOT rocket science!!! It is EASY to design to have enough thickness, no need of super engineers!!! People are just CARELESS or don't give a crab. How can those stupid people let it go with only 0.03"?!!!


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## tkdroamer (Nov 7, 2022)

Alan0354 said:


> I don't know what is "open" design. I can assure you MOST if not ALL folding knives look like that. I have more than 10 myself from different brands, this is a good representative of how it looks.
> 
> The bearings diameter is NOT a lot bigger than the center hole.
> View attachment 29265
> ...


You must be looking at the ID of the bearing. Look at it from the OD.


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## Alan0354 (Nov 7, 2022)

tkdroamer said:


> You must be looking at the ID of the bearing. Look at it from the OD.


I have no idea how all your questions and comments has anything to do with what I said, you need to describe in more detail what you mean and what your concerns are.

I think I made it as simple as I can explaining with pictures and descriptions. Treat me as simple person, elaborate more. I don't have a high degree, I go by common sense and instincts.


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## jks9199 (Nov 7, 2022)

Nobody's going to convince you.  Amazingly enough, things aren't designed around being used improperly; they're designed for use in the way they're intended to be used.  Cars are not made to survive being dropped on their roofs; they're designed to handle impacts in the relatively normal lines that they'll encounter.  They're also not (generally) designed to drive up walls.

The ball bearing design is widely used.  That's a clue that it's not failing often, when the knife is used in a reasonable manner.  The tip of a knife can be used as pry-tool or screwdriver -- but it's likely to break the tip off because that's not what it's designed to do.

Use tools in the proper manner; if you abuse them, they'll fail you.


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## Alan0354 (Nov 7, 2022)

jks9199 said:


> Nobody's going to convince you.  Amazingly enough, things aren't designed around being used improperly; they're designed for use in the way they're intended to be used.  Cars are not made to survive being dropped on their roofs; they're designed to handle impacts in the relatively normal lines that they'll encounter.  They're also not (generally) designed to drive up walls.
> 
> The ball bearing design is widely used.  That's a clue that it's not failing often, when the knife is used in a reasonable manner.  The tip of a knife can be used as pry-tool or screwdriver -- but it's likely to break the tip off because that's not what it's designed to do.
> 
> Use tools in the proper manner; if you abuse them, they'll fail you.


No, it is so important for cars to survive dropping on the roof that it's one of the *government SAFETY standard(NHTSA) that has to pass before any car can be sold here*. I believe it's at least 3 times the weight of the car. That's why IIHC test it to 5 times the weight.

Any knife can work decently "as designed". It's the ones that can survive better in unexpected but useful ways that shines.

Yes, it's important for knives to be able to pry, most common is in car accident that you have to pry your way out. You don't carry a pry bar with you, likely you have one tool and that tool has to be able to do other task. That's the reason there are plenty of knives with seat belt cutter. And don't tell me you can have a pry bar in the glove compartment. What if you are not driving? What if you are sitting in the back seat? Even if you are driving, what if you cannot reach the glove compartment? You have ONLY ONE tool, you want it to be as versatile as possible. AND YES, there are plenty of knives design for that(supposedly).

One cannot be narrow minded.



Like I stressed, I got a few that are tough enough for prying and all. This is ONLY a discussion of the theory, NOT whether we need it.


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## Rich Parsons (Nov 7, 2022)

Alan0354 said:


> No, it is so important for cars to survive dropping on the roof that it's one of the *government SAFETY standard(NHTSA) that has to pass before any car can be sold here*. I believe it's at least 3 times the weight of the car. That's why IIHC test it to 5 times the weight.
> 
> Any knife can work decently "as designed". It's the ones that can survive better in unexpected but useful ways that shines.
> 
> ...



Hi Alan, 





__





						Loading…
					





					www.nhtsa.gov
				





From the article and Federal Document above 

"Executive Summary a. Final rule As part of a comprehensive plan for reducing the serious risk of rollover crashes and the risk of death and serious injury in those crashes, this final rule upgrades Federal Motor Vehicle Safety Standard (FMVSS) No. 216, Roof Crush Resistance. For the vehicles currently subject to the standard, passenger cars and multipurpose passenger vehicles, trucks and buses with a GVWR of 2,722 kilograms (6,000 pounds) or less, the rule doubles the amount of force the vehicle’s roof structure must withstand in the specified test, from 1.5 times the vehicle’s unloaded weight to 3.0 times the vehicle’s unloaded weight. The rule also extends the applicability of the standard so that it will also apply to vehicles with a GVWR greater than 2,722 kilograms (6,000 pounds), but not greater than 4,536 kilograms 6 (10,000 pounds), establishing a force requirement of 1.5 times the vehicle’s unloaded weight for these heavier vehicles."

It is required to be between 1.5 to 3 times. 
And 1.5 times for the those above 6000 lbs and below 10000 lbs. 

A further part of the same section has the following quote:

"While this rulemaking action to improve roof strength is part of our comprehensive plan for addressing the serious problem of rollover crashes, this action, by itself, addresses a relatively small subset of that problem. There are more than 10,000 fatalities in rollover crashes each year. To address that problem, our comprehensive plan includes actions to (1) reduce the occurrence of rollovers, (2) mitigate ejection, and (3) enhance occupant protection when rollovers occur (improved roof crush resistance is included in this third category). Our analysis shows that of the more than 10,000 fatalities that occur in rollover crashes each year, roof strength is relevant to only about seven percent (about 667) of those fatalities. We estimate that today’s rule will prevent 135 of those 667 fatalities."


and then 

"The portions of our comprehensive plan that will have the highest life-saving benefits are the ones to reduce the occurrence of rollovers (prevention) and to mitigate ejection (occupant containment). We estimate that by preventing rollovers, electronic stability control (ESC) will reduce the more than 10,000 fatalities that occur in rollover crashes each year by 4,200 to 5,500 fatalities (and also provide significant additional life-saving benefits by preventing other types of crashes). In the area of mitigating ejection, significant life-benefits are and/or will occur by our continuing efforts to increase seat belt use and our upcoming rulemaking on ejection 8 mitigation. A more complete discussion of our comprehensive plan is discussed later in this document."

The concentration on testing and directions for improvement are in the areas where more deaths occur. 
About 42% to 55%
Which is roll over events.


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## Alan0354 (Nov 7, 2022)

Ha ha, I am a lot more familiar about car safety than knives!!!

The original intention of this thread is resolved already, I got my knives that is very tough already. We are just talking theory at this point. Talking about car safety is just as good!!!

Actually the strong roof is a whole lot more important than people realize. It is NOT just about strong roof to protect occupants on roll over. It strengthen the safety on other collisions of a car. To have a strong roof, you have to have* strong A-pillars and B-pillars*. That is very important for safety on side collision. Those two pillars are just as important as the cross beam inside the door for side impact(remember, the strong door has to link to something strong to *hold the door in place*). Also, the A-pillar with a rigid roof form the two anchor point for front collision. Remember most cars are unit body, the whole front of the car(with the engine) is linked to the passenger compartment by two big rail under the two front doors AND the two A-pillars. THAT'S IT!!! The two A-pillars ARE like two of the legs of a 4 legs table. People don't realize how important the A-pillars and the roof in head-on or offset front end collision safety.

That's the reason I would never buy a convertible car no matter what. You lose two legs of the table, you can never strengthen the lower two rails enough to make up losing the two A-pillars. I would have bought a Corvette long time ago if not for that. Also a true convertible loses the two B-pillars also( Corvette do have the roll bar in place of the B-pillar.).

When I buy cars, safety is the FIRST and the most important thing I consider.....Over reliability and everything else.


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## tkdroamer (Nov 8, 2022)

Alan0354 said:


> I have no idea how all your questions and comments has anything to do with what I said, you need to describe in more detail what you mean and what your concerns are.
> 
> I think I made it as simple as I can explaining with pictures and descriptions. Treat me as simple person, elaborate more. I don't have a high degree, I go by common sense and instincts.


You are looking at the INSIDE DIMENSION of the hole for the pin instead of the OUTSIDE DIMENSION of the whole bearing.


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## tkdroamer (Nov 8, 2022)

Alan0354 said:


> No, it is so important for cars to survive dropping on the roof that it's one of the *government SAFETY standard(NHTSA) that has to pass before any car can be sold here*. I believe it's at least 3 times the weight of the car. That's why IIHC test it to 5 times the weight.
> 
> Any knife can work decently "as designed". It's the ones that can survive better in unexpected but useful ways that shines.
> 
> ...


What if a frog had a clutch? It would not jump.


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## Gerry Seymour (Nov 8, 2022)

Alan0354 said:


> Let me show another picture of the knife that actually has very thin part, the Sencut Acumen. The thickness is only 0.03". Look at the gap between the side and the blade on both sides are WIDER than the one in the last post.
> View attachment 29264
> 
> Look at it, there is NOT SUPPORT of the blade other than the ball bearings on both sides.....until it cracks. Also, notice the frame lock metal is NOT as thick as the other one, it can easily slip if the blade start to wobble.


Excellent. You're looking at structure now.

Now, how much force is being exerted on that thin part under reasonable stress (prying a can lid, perhaps)? You have to have a reasonable estimate of that to determine how much force is placed on point (not quite a point, but close enough for our purposes) of each bearing's contact with that area. Once you have that figured, you have to factor that it's reinforced from the other side. While that counter-force is likely not on the same point (that'd be impossible to maintain in real-world production), it's near enough to counter most of that. Unless the metal is brittle (which would be a larger problem for the knife), it's unlikely that metal - being supported from both sides with very small spans between supports, and being supported around with thicker metal - would fail under most reasonable force.


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## Gerry Seymour (Nov 8, 2022)

tkdroamer said:


> A bearing will move more freely under the load a knife would typically see, assuming as you say the connection or assembly is correct.
> The heaviest recording moving (not rolling) loads are on thrust bearings (flat bearings, aka washers).
> It is amazing the variation in bearing quality. Two bearings can have the exact same numbers stamped on them and the life cycle and load they can handle be very different.


That makes sense. I think my question wasn't clear - I was asking about the basic usability, the ability to open the knife with reasonable force. I'd assume you could more easily (i.e. with less force) move a load on a roller bearing (ball or conical) than on a thrust bearing, just because of the friction involved. Would that be correct?


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## Gerry Seymour (Nov 8, 2022)

Alan0354 said:


> Guys, this is NOT something I discover, They know about it. There are few that are thick in that part. Here are the pictures of 3 of mine that are thick:
> 
> Off-Grid Baby Rhino with thickness of *0.073"*:
> View attachment 29266
> ...


You refer to "enough thickness" - for what force? This goes back to my comment a few minutes ago that you'd need to know the forces involved (and include that the area in question is supported on both sides and has thicker material surrounding it) to know what thickness is necessary with a given material.

It's entirely possible that different knives use different thicknesses for reasons other than what you're supposing. A few that come to mind: differences in material, differences in tolerances (design or production parameters), type of bearing (more balls or thrust bearing), more surrounding material, size of gap, etc.


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## Gerry Seymour (Nov 8, 2022)

Alan0354 said:


> No, it is so important for cars to survive dropping on the roof that it's one of the *government SAFETY standard(NHTSA) that has to pass before any car can be sold here*. I believe it's at least 3 times the weight of the car. That's why IIHC test it to 5 times the weight.
> 
> Any knife can work decently "as designed". It's the ones that can survive better in unexpected but useful ways that shines.
> 
> ...


I'm not sure what you think you'll need to or be able to pry out of in a car accident. Cars have lots of glass - a knife with a glass break and belt cutter is much more likely to help in that scenario.

If you're looking for reasonable prying (like paint can lids, etc.), some knives will survive that, but it's far from what they're designed for, and it puts most of the pressure at the tip (where it's likely to fail long before the tang-to-handle connection).


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## frank raud (Nov 8, 2022)

Gerry Seymour said:


> Excellent. You're looking at structure now.
> 
> Now, how much force is being exerted on that thin part under reasonable stress (prying a can lid, perhaps)? You have to have a reasonable estimate of that to determine how much force is placed on point (not quite a point, but close enough for our purposes) of each bearing's contact with that area. Once you have that figured, you have to factor that it's reinforced from the other side. While that counter-force is likely not on the same point (that'd be impossible to maintain in real-world production), it's near enough to counter most of that. Unless the metal is brittle (which would be a larger problem for the knife), it's unlikely that metal - being supported from both sides with very small spans between supports, and being supported around with thicker metal - would fail under most reasonable force.


It's almost like knives break at the tip or the middle of the blade. But then real world examples are apparently not common sense.


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## Alan0354 (Nov 8, 2022)

frank raud said:


> It's almost like knives break at the tip or the middle of the blade. But then real world examples are apparently not common sense.


How many times I STRESSED the tip of the blade is the most critical? Then if the tip is fat, you move down to the next weak point and the next. You read the thread? 

There are plenty knives with robust pivot point, I ALREADY found all the knives I needed, this is just talking at this point.

If you even care to look for torture and look at what knives they tested, MAJORITY of them are WITHOUT ball bearings like Cold Steel etc. There's good reason why the ones with reputation DO NOT use ball bearings.

You use common sense, but you DO NOT blind guess and assume.


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## frank raud (Nov 8, 2022)

Alan0354 said:


> How many times I STRESSED the tip of the blade is the most critical? Then if the tip is fat, you move down to the next weak point and the next. You read the thread?
> 
> There are plenty knives with robust pivot point, I ALREADY found all the knives I needed, this is just talking at this point.
> 
> ...


So, a knife blade has to break in two places before the pivot is a concern for breakage? Could that be why you never see a knife break at the pivot?


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## Alan0354 (Nov 8, 2022)

tkdroamer said:


> You are looking at the INSIDE DIMENSION of the hole for the pin instead of the OUTSIDE DIMENSION of the whole bearing.


I have no idea what you are talking about the outside dimension of the whole bearing. Here is my drawing in more detail with a real picture, let me know what you are talking.

This is the drawing:





This is a real picture with the label so we can speak on the same page:





Let me know what you are talking about.


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## Alan0354 (Nov 8, 2022)

frank raud said:


> So, a knife blade has to break in two places before the pivot is a concern for breakage? Could that be why you never see a knife break at the pivot?


Could be, but I am talking about this particular point BECAUSE you cannot judge until you open the knife. The tip and the middle of the knife is easy to judge just by looking at it.

More importantly, this is NOT rocket science. I already have THREE knives with ball bearings that is plenty thick showed in post #104 if you care to read before commenting. It is crappy engineering, people do realize that can be a weak point. 

AS I SAID many times, most of the proven rugged knives do NOT use ball bearing, you follow what I am talking? 

There are knives that have thick enough on that part shown in post #104, do you follow what I said?

I am picking on this weak point BECAUSE you cannot see it until you buy it and open it, do you follow what I said?

I show you cannot judge by the outer appearance like my Sancut Acumen, that looks thick and tough outside, but only 0.03" in the critical part shown in post #103. Do you read and follow what I said?


Did you watch those torture videos, and look into all the ones that survived? You find out whether those have ball bearings? They praised Cold Steel a lot.....that do NOT use ball bearings. Did you research into that?


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## Alan0354 (Nov 8, 2022)

Guys, I repeated many times that this is NOT the most critical part of the folding knife, there are more critical things to look. BUT THIS IS SO FAR THE ONLY PART THAT YOU CANNOT SEE UNTIL YOU BUY IT AND OPEN IT UP.

Of cause there are more critical part, the tip of the knife, the middle of the blade, even the thickness of the steel frame for a liner lock are important.

Also how much the liner lock goes UNDER the bottom of the blade is critical( the liner that move under the blade to lock the blade in position). You want to liner goes farther under the blade to make it harder to slip out and unlock the blade.

Also if you move farther back of the handle, how many support to stabilize the two steel plate in the handle. I've seen knives only use ONE single screw to hold the two sides together.

These are things to look out when buying a knife, BUT except the thickness of that part I talked about,* EVERYTHING ELSE CAN BE SEEN JUST BY LOOKING AT THE KNIFE. That's what make what I said here more important because you cannot see it.*


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## Alan0354 (Nov 8, 2022)

Gerry Seymour said:


> Excellent. You're looking at structure now.
> 
> Now, how much force is being exerted on that thin part under reasonable stress (prying a can lid, perhaps)? You have to have a reasonable estimate of that to determine how much force is placed on point (not quite a point, but close enough for our purposes) of each bearing's contact with that area. Once you have that figured, you have to factor that it's reinforced from the other side. While that counter-force is likely not on the same point (that'd be impossible to maintain in real-world production), it's near enough to counter most of that. *Unless the metal is brittle (which would be a larger problem for the knife), i*t's unlikely that metal - being supported from both sides with very small spans between supports, and being supported around with thicker metal - would fail under most reasonable force.


I have been talking about the structure all along with all the drawings and pictures!!!

I don't have the data and not easy to get, that's why I am talking here.

*I think I forgot to mention one of the most important thing so far WHY I make a big deal on this. It's the brittleness of the blade. If the steel is NOT brittle, 0.03" thick is PLENTY.*

Problem is nobody knows how well the blade is QUENCHED. If it's not done right, it can be brittle. I hate to say being a Chinese, I do NOT trust things from CHINA, they have really BAD attitude from the communist days. They fake, look the other way, sloppy..........They just want to get things out the door. I don't trust their blades BUT I am not willing to pay an arm or a leg. So I look out for these stuffs.

There are so many other things that are sloppy on the knives I have, I am talking about up to $70, not S&W cheap stuffs. 70% of the pivot screw on all my knives CANNOT be tighten, the blade will get stuck if you tighten the screw. You have to back off like 1/2 a turn or so. You know what the do? They use *thread lock to keep the screw in place *without tightening it!!! I have to work on thinning the G10 cover to get it just right so I can tighten the screw.

Even if I pay a lot, what guaranty the quench is correct? So it's just saver to find those at least 0.05" thick instead of settling with thin ones.


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## Gerry Seymour (Nov 8, 2022)

Alan0354 said:


> Could be, but I am talking about this particular point BECAUSE you cannot judge until you open the knife. The tip and the middle of the knife is easy to judge just by looking at it.
> 
> More importantly, this is NOT rocket science. I already have THREE knives with ball bearings that is plenty thick showed in post #104 if you care to read before commenting. It is crappy engineering, people do realize that can be a weak point.
> 
> ...


You're assuming some knives don't use ball bearings for the reasons you suspect. But you don't know that. Another possible explanation is that those bearings are more subject to fouling than a thrust bearing, so they avoid them for that reason. Another is that they make the effort to maintain tighter tolerances and smoother surfaces, so the thrust bearings work well (while they may not otherwise).

You've yet to show any evidence that this is, in fact, a point of likely failure in normal or reasonable use - with or without the ball bearings or thinner area.


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## Alan0354 (Nov 8, 2022)

Gerry Seymour said:


> You're assuming some knives don't use ball bearings for the reasons you suspect. But you don't know that. Another possible explanation is that those bearings are more subject to fouling than a thrust bearing, so they avoid them for that reason. Another is that they make the effort to maintain tighter tolerances and smoother surfaces, so the thrust bearings work well (while they may not otherwise).
> 
> You've yet to show any evidence that this is, in fact, a point of likely failure in normal or reasonable use - with or without the ball bearings or thinner area.


I searched for thrust bearings, those are all thrust bearings as seen in the many pictures, those are balls fixed into the round brass thing.

OF CAUSE I have no evidence, it's a PREDICTION according to the thickness, I am not going to break my Sancut to prove, just looking at the structure to predict.

Like I clarified, if the blade is NOT brittle, 0.03" is good enough, BUT can you rely on that it's done right and it's not brittle?

Like I said, a lot of the torture test were done on knives with no thrust or ball bearings. Show that doesn't proof anything if they don't break at the pivot point.


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## jks9199 (Nov 8, 2022)

Gerry Seymour said:


> I'm not sure what you think you'll need to or be able to pry out of in a car accident. Cars have lots of glass - a knife with a glass break and belt cutter is much more likely to help in that scenario.
> 
> If you're looking for reasonable prying (like paint can lids, etc.), some knives will survive that, but it's far from what they're designed for, and it puts most of the pressure at the tip (where it's likely to fail long before the tang-to-handle connection).


For a car crash and breaking glass... use a spring loaded centerpunch.  Force is concentrated onto a pin-point, and it doesn't require you to do more than push. 

Prying with knives... if the tip doesn't snap, there's a good chance the blade will bend...  But, in the crashes I've either personally investigated or reviewed reports on -- damn few (none as far as I recall) involved a self-rescue that needed prying.  The Jaws of Life or a Sawz-all... Yeah.  But those aren't self-rescue.


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## tkdroamer (Nov 9, 2022)

Alan0354 said:


> I have no idea what you are talking about the outside dimension of the whole bearing. Here is my drawing in more detail with a real picture, let me know what you are talking.
> 
> This is the drawing:
> View attachment 29279
> ...


When both bearings are installed, are they not slightly thicker than the thickness of the knife (or at least flush)? Effectively, the OD of the bearing distributes the load all around the section you have listed as 'outer'.


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## tkdroamer (Nov 9, 2022)

Gerry Seymour said:


> That makes sense. I think my question wasn't clear - I was asking about the basic usability, the ability to open the knife with reasonable force. I'd assume you could more easily (i.e. with less force) move a load on a roller bearing (ball or conical) than on a thrust bearing, just because of the friction involved. Would that be correct?


Correct, with exceptions. There will be more frictional loss with flat surface bearings, but the uniformity of the surface means they can handle massive loads. 
There are several applications where wooden bearings are still used. Some environments will destroy metal or alloy bearings prematurely. That is pretty cool to me.


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## Gerry Seymour (Nov 9, 2022)

Alan0354 said:


> I searched for thrust bearings, those are all thrust bearings as seen in the many pictures, those are balls fixed into the round brass thing.
> 
> OF CAUSE I have no evidence, it's a PREDICTION according to the thickness, I am not going to break my Sancut to prove, just looking at the structure to predict.
> 
> Like I clarified, if the blade is NOT brittle, 0.03" is good enough, BUT can you rely on that it's done right and it's not brittle?


Again, your prediction is based on an assumption. As for brittle metal, if it was brittle, it wouldn't do well in other torture tests, so those are a good guide.


Alan0354 said:


> Like I said, a lot of the torture test were done on knives with no thrust or ball bearings. Show that doesn't proof anything if they don't break at the pivot point.


As for that, you seem to be saying that what they chose to test is proof that what they didn't choose was not going to survive the test. Which would be an assumption. And a good example of confirmation bias.


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## tkdroamer (Nov 9, 2022)

Alan0354 said:


> I searched for thrust bearings, those are all thrust bearings as seen in the many pictures, those are balls fixed into the round brass thing.
> 
> OF CAUSE I have no evidence, it's a PREDICTION according to the thickness, I am not going to break my Sancut to prove, just looking at the structure to predict.
> 
> ...


Please, do not intentionally break a perfectly good knife.


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## Alan0354 (Nov 9, 2022)

tkdroamer said:


> When both bearings are installed, are they not slightly thicker than the thickness of the knife (or at least flush)? Effectively, the OD of the bearing distributes the load all around the section you have listed as 'outer'.


No!!! The outer part of the thrust bearings do NOT touch the thin part of the blade. It's the little balls that is in contact of the blade at the *RED* circle. That's how thrust bearings are. The brass round part ONLY hold the balls together. Also, the brass part is very thin, some knives even use plastic for that. 

So all the pressure is on the RED circle.


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## Alan0354 (Nov 9, 2022)

Gerry Seymour said:


> Again, your prediction is based on an assumption. As for brittle metal, if it was brittle, it wouldn't do well in other torture tests, so those are a good guide.
> 
> As for that, you seem to be saying that what they chose to test is proof that what they didn't choose was not going to survive the test. Which would be an assumption. And a good example of confirmation bias.


I am not talking about definite failure, it's not the most critical part of the knife, the tip is more critical. BUT I want PERFECTION!!!!

I want to find those that are strong all around.....AND there are plenty, it's not that I ask for impossible. I ALREADY found 3 with ball bearings that are plenty thick already. Why do I want to settle when I buy the next one? Besides there are ones without ball bearings, why do I have to accept anything with the slightest potential to have problem?


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## Alan0354 (Nov 9, 2022)

tkdroamer said:


> When both bearings are installed, are they not slightly thicker than the thickness of the knife (or at least flush)? Effectively, the OD of the bearing distributes the load all around the section you have listed as 'outer'.


If you talk about thrusting(shanking), IF the OD of the thrust bearings are very tight fit to the blade, that MIGHT help a little, But I tell you, they are NOT tightly fit. They literally drops out. A lot of knives use plastic also. But for prying, that does not help at all, the pressure is ALL on the RED circle.


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## Gerry Seymour (Nov 9, 2022)

Alan0354 said:


> I am not talking about definite failure, it's not the most critical part of the knife, the tip is more critical. BUT I want PERFECTION!!!!
> 
> I want to find those that are strong all around.....AND there are plenty, it's not that I ask for impossible. I ALREADY found 3 with ball bearings that are plenty thick already. Why do I want to settle when I buy the next one? Besides there are ones without ball bearings, why do I have to accept anything with the slightest potential to have problem?


Again, you're talking as if you know this to be a likely point of failure. If that's not the case, you're putting a lot of focus on the wrong things - and you haven't shown anything to suggest this actually is a likely point of failure.


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## tkdroamer (Nov 9, 2022)

Alan0354 said:


> If you talk about thrusting(shanking), IF the OD of the thrust bearings are very tight fit to the blade, that MIGHT help a little, But I tell you, they are NOT tightly fit. They literally drops out. A lot of knives use plastic also. But for prying, that does not help at all, the pressure is ALL on the RED circle.


I am not aware of a knife blade made for prying. I still remember the 'beating' I got as a kid when I snapped my dad's favorite filleting knife that was in a piece of wood.


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## tkdroamer (Nov 9, 2022)

Alan0354 said:


> No!!! The outer part of the thrust bearings do NOT touch the thin part of the blade. It's the little balls that is in contact of the blade at the *RED* circle. That's how thrust bearings are. The brass round part ONLY hold the balls together. Also, the brass part is very thin, some knives even use plastic for that.
> 
> So all the pressure is on the RED circle.


That would mean the load is on whatever the diameter of the balls would be, not the pin in the middle, assuming the fit is decent.


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## Alan0354 (Nov 9, 2022)

tkdroamer said:


> I am not aware of a knife blade made for prying. I still remember the 'beating' I got as a kid when I snapped my dad's favorite filleting knife that was in a piece of wood.


Yes, it's NOT meant for prying, I want to have one that can stand up to prying. Car is meant for driving from point A to B, why people want big engine to go from 0-60 in in 4sec? BECAUSE THEY WANT IT!!!

Seems like people *never get the point that's what I want*, I am NOT asking whether it is necessary, I am asking about the design. It's like keep asking why the person want a car that can go from 0-60 in 4sec!!! That's what the person wants!!!

Ha ha, if it's not for the concern of the roof of the Corvette, I would have bought one even though it only seat 2, can't carry much of anything, not good in gas millage, not that reliable........... I just want it!!!


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## Alan0354 (Nov 9, 2022)

tkdroamer said:


> That would mean the load is on whatever the diameter of the balls would be, not the pin in the middle, assuming the fit is decent.


That's what I've been talking from the very beginning, that's why I never follow what you are talking. For prying, all the force is on the RED ring of balls only. If you read back all my posts, it's all about that.

The ONLY thing that was in my mind and* I FORGOT to mention* out loud was that I worry about the blade can be* BRITTLE*(if they did not quench correctly), 0.03" is to thin to withstand the force if it is brittle. If the blade is quenched correctly, even 0.03" is not going to be a problem. I just don't trust anything from CHINA, so I want it to be thicker like 0.05" or thicker.

I guess I watched too many "Forge In Fire" tv show seeing all the blades cracked because of quenching problem.


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## tkdroamer (Nov 10, 2022)

Alan0354 said:


> That's what I've been talking from the very beginning, that's why I never follow what you are talking. For prying, all the force is on the RED ring of balls only. If you read back all my posts, it's all about that.
> 
> The ONLY thing that was in my mind and* I FORGOT to mention* out loud was that I worry about the blade can be* BRITTLE*(if they did not quench correctly), 0.03" is to thin to withstand the force if it is brittle. If the blade is quenched correctly, even 0.03" is not going to be a problem. I just don't trust anything from CHINA, so I want it to be thicker like 0.05" or thicker.
> 
> I guess I watched too many "Forge In Fire" tv show seeing all the blades cracked because of quenching problem.


But I think you are still missing the OD sphere of the bearings. Even though a thrust bearing does not have an outer race, the ball bearings are rolling/resting on something. Effectively, the centerline of the ball would define the OD of the bearings supporting surface.


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## tkdroamer (Nov 10, 2022)

Alan0354 said:


> Yes, it's NOT meant for prying, I want to have one that can stand up to prying. Car is meant for driving from point A to B, why people want big engine to go from 0-60 in in 4sec? BECAUSE THEY WANT IT!!!
> 
> Seems like people *never get the point that's what I want*, I am NOT asking whether it is necessary, I am asking about the design. It's like keep asking why the person want a car that can go from 0-60 in 4sec!!! That's what the person wants!!!
> 
> Ha ha, if it's not for the concern of the roof of the Corvette, I would have bought one even though it only seat 2, can't carry much of anything, not good in gas millage, not that reliable........... I just want it!!!


Okay, don't harden the blade steel. It will never stay sharp, but it will bend before it breaks.


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## Alan0354 (Nov 10, 2022)

tkdroamer said:


> But I think you are still missing the OD sphere of the bearings. Even though a thrust bearing does not have an outer race, the ball bearings are rolling/resting on something. Effectively, the centerline of the ball would define the OD of the bearings supporting surface.


I still don't know what you are talking exactly, you talking about the OD of EACH or the small little balls that are rolling around in the RED circle?

If that's the case, I don't agree. The ball only TOUCH the flat surface at a PIN POINT, it's a point contact, OD of the little ball has very little to do with in.


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## Alan0354 (Nov 10, 2022)

tkdroamer said:


> Okay, don't harden the blade steel. It will never stay sharp, but it will bend before it breaks.


NO, it is very basic knowledge for anyone into knives that the two character of steel can not co-exist, either you get edge retention, or you get toughness. For edge, you need HARD steel, but you loses toughness, you want toughness, you loses edge retention. There are ones in around HRC 59-61 like D2 or 9Cr18MoV that has reasonable edge retention and not that brittle. Those knives are in the range of $40 to $100.

That's why I stay in the range of $40 to $80. I don't go for expensive ones, not only they use steel for edge retention, something about the expensive ones that they are just NOT designed for self defense, more for showing off and looks different. Knives like from Spyderco is dangerous for thrusting as there's nothing to stop the knife from being shoved back into the hand like this:
S™ - Spyderco, Inc.

Too bad Cold Steel don't have flipper tap on the blade that I want. It's a good compromise of price and durability. Looks like Steel Will is the main brand for me.

Like I said, I am NOT looking for advice what to buy, I ALREADY have quite a few that are sturdy, D2 or 9Cr18Mov with either no ball bearings or with thick enough of the part of concern.

I demand perfection, I bought a second Steel Will, it's Cutjact 3.5" blade. I spent two days working on it, honing the bronze bearing so smooth that the knife open like the ones with ball bearings. Grind the frame lock so it goes deeper into the bottom of the blade so it's safer. I have good knives.

I am talking about theory and whoever still interest, we can talk. How much are you into knives?


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## Dirty Dog (Nov 10, 2022)

Alan0354 said:


> NO, it is very basic knowledge for anyone into knives that the two character of steel


Blade steel has four characteristics, not two. This is basic knowledge for anyone into knives.


Alan0354 said:


> can not co-exist, either you get edge retention, or you get toughness.


This "impossible" conjoining of hard and tough is, in fact, the purpose of heat treating a blade, especially differential heat treating. It is also one of the primary reasons things like San Mai exist.
But you won't find that in a $40 knife.



Alan0354 said:


> For edge, you need HARD steel, but you loses toughness, you want toughness, you loses edge retention. There are ones in around HRC 59-61 like D2 or 9Cr18MoV that has reasonable edge retention and not that brittle. Those knives are in the range of $40 to $100.


Hardness is more a function of the heat treating choices than the material choice. Yes, it is easier to get a higher HRC with more carbon, but if you know what you're about, you can get pretty much any blade material to any HRC.


Alan0354 said:


> That's why I stay in the range of $40 to $80. I don't go for expensive ones, not only they use steel for edge retention, something about the expensive ones that they are just NOT designed for self defense, more for showing off and looks different.


This is utter nonsense. 




That's not a knife that was designed for self defense?




How about that one? Bear in mind I own and carry both of them and I am quite confident either one would be very effective as a self defense tool.
Of course, I wouldn't want to use either as a pry bar. But that's ok. I have pry bars too.


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## Alan0354 (Nov 10, 2022)

Dirty Dog said:


> Blade steel has four characteristics, not two. This is basic knowledge for anyone into knives.
> 
> This "impossible" conjoining of hard and tough is, in fact, the purpose of heat treating a blade, especially differential heat treating. It is also one of the primary reasons things like San Mai exist.
> But you won't find that in a $40 knife.
> ...


I would NOT carry either one of these, there is NO protection from being shoved back into your hand when thrusting. I want ones that look like these:





With long tap sticking out to prevent the knife from being shoved back into the hand.

Those are very strong knives that has much better chance to survive prying for sure. The lower one is with ball bearings.

Of cause heat treat makes the main difference, but the steel composition makes a big difference also. I read a lot of steel for blades,* if all heat treatments are equal*, they talk about two main types, either optimized for edge retention OR toughness. You cannot have both. Of cause there *are many different type of steel in terms of compositions. *But you can either optimize for edge retention(hardness) but brittle, or softer type that is tougher and hard to break, but not good in edge retention.  I choose D2 or equivalent that is not that hard, but not that brittle. Price is middle of the road also.


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## Alan0354 (Nov 10, 2022)

tkdroamer said:


> But I think you are still missing the OD sphere of the bearings. Even though a thrust bearing does not have an outer race, the ball bearings are rolling/resting on something. Effectively, the centerline of the ball would define the OD of the bearings supporting surface.


You disagree, but I still have trouble understanding what you are talking about. Maybe you can educate me why.


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## tkdroamer (Nov 11, 2022)

Alan0354 said:


> You disagree, but I still have trouble understanding what you are talking about. Maybe you can educate me why.


You misunderstand what I am saying. From the center point of one ball bearing to the center point of the ball bearing on the opposite defines the diameter of a circle. Each ball bearing is part of that circle and work together. 
Never is the blade surface resting on only one ball bearing.


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## Dirty Dog (Nov 11, 2022)

Alan0354 said:


> I would NOT carry either one of these, there is NO protection from being shoved back into your hand when thrusting. I want ones that look like these:


Certainly there is. I have tested those designs in actual use (not on people) by cutting and thrusting into objects that are much harder to penetrate than a human. Without having any problems with my hand sliding up towards the blade. Maybe you need to work on your grip?


Alan0354 said:


> Of cause heat treat makes the main difference, but the steel composition makes a big difference also. I read a lot of steel for blades,* if all heat treatments are equal*, they talk about two main types, either optimized for edge retention OR toughness.


I read a lot too, but unlike you I apply that reading. I use blades. I *make* blades. And what you write above is stupid.
Because heat treatments are not equal. The heat treatment is performed with the end goal in mind, and varies accordingly. It's the equivalent of saying all vehicles, whether a tiny econobox city commuter or a long haul cargo hauler, should all have the same engine.

A well made blade is not optimized for edge retention or hardness. The blade, guard, handle materials and shapes, and the heat treatment, are optimized for the intended usage. But that, again, isn't a factor in cheap throw-away knives.

Form follows function. And you can't buy a Yugo and expect it to perform like a Corvette. You seem to struggle with these concepts.


Alan0354 said:


> You cannot have both.


In fact, you can. But not for pocket change.


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## Alan0354 (Nov 11, 2022)

Dirty Dog said:


> Certainly there is. I have tested those designs in actual use (not on people) by cutting and thrusting into objects that are much harder to penetrate than a human. Without having any problems with my hand sliding up towards the blade. Maybe you need to work on your grip?


I practice a lot in thrusting on the heavy bag, it does slip if it doesn't have that. Problem is you are NOT supposed to squeeze it tight, you only squeeze on contact just like punching, you suppose to relax until you are about to contact, then you squeeze the fist. 

Problem is in the middle of everything, your timing might be off. For punching, it's no big deal, you don't hit as hard. BUT for knife, the knife can be shoved into your hand and you cut tendons and all!!! It's a chance you do NOT want to take.

I actually filed down on my first plastic knife to experiment, it did not shove all the way, BUT it did got pushed in enough it will cut my index finger if it were a real one. I had to buy a new plastic knife.

You ever actually thrust into a heavy bag to practice? You'll find out really fast.


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## Alan0354 (Nov 11, 2022)

tkdroamer said:


> You misunderstand what I am saying. From the center point of one ball bearing to the center point of the ball bearing on the opposite defines the diameter of a circle. Each ball bearing is part of that circle and work together.
> Never is the blade surface resting on only one ball bearing.


I assume that from the start, that's why I drew a RED ring. Read post #84 again. Read the first two sentence, I already assume the force is applied evenly along the WHOLE RED ring without slack if you read my posts carefully. This is common sense!!! That's why I never follow what you said because I already spelled out loud and clear, and when you raise question, I assume it's something else.

Read post #84 again, my concern is the CRITICAL distance in GREEN between the RED circle(which you are talking about the OD of the those balls) to the edge where the blade trasition from thin to thick. If the distance is large enough, the thick part of the blade is not very helpful in strengthen it. The top drawing is very typical with the real thing on all the knives.


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## Rich Parsons (Nov 11, 2022)

Alan0354 said:


> I practice a lot in thrusting on the heavy bag, it does slip if it doesn't have that. Problem is you are NOT supposed to squeeze it tight, you only squeeze on contact just like punching, you suppose to relax until you are about to contact, then you squeeze the fist.
> 
> Problem is in the middle of everything, your timing might be off. For punching, it's no big deal, you don't hit as hard. BUT for knife, the knife can be shoved into your hand and you cut tendons and all!!! It's a chance you do NOT want to take.
> 
> ...



Step one: 
Buy a Beef Roast
Step two:
Identify a fresh washed pair of jeans you no longer want. 
Step three:
Place Roast into Pant leg. 
Step four:
Practice Thrusts, stabs, slicing and slashes. 

Step five:
Remove Jeans from Roast
Step six:
Review cuts and stabs (* This can be done through out the process *)

Step seven:
When done, get cutting board and finish cutting up roast into pieces and place in crock pot for beef stew or chili or something else. 
Little to no waste. 
And if others in the household were out during the process then they are no wiser to one's practice.


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## frank raud (Nov 11, 2022)

Alan0354 said:


> I practice a lot in thrusting on the heavy bag, it does slip if it doesn't have that. Problem is you are NOT supposed to squeeze it tight, you only squeeze on contact just like punching, you suppose to relax until you are about to contact, then you squeeze the fist.


Uumm, where did you learn to not hold a knife tightly at all times? This goes against what I have been taught by multiple instructors.


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## Alan0354 (Nov 11, 2022)

frank raud said:


> Uumm, where did you learn to not hold a knife tightly at all times? This goes against what I have been taught by multiple instructors.


It's talked on a video from an expert. You should squeeze the knife only at the point of contact and relax the other time. If you squeeze the knife all the time, you slow down, it's like the whole arm is tight and you cannot move as fast. I just apply the same idea as punching that relax the arm and fist to throw the punch, then tighten up at the point of contact.


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## frank raud (Nov 11, 2022)

Alan0354 said:


> It's talked on a video from an expert. You should squeeze the knife only at the point of contact and relax the other time. If you squeeze the knife all the time, you slow down, it's like the whole arm is tight and you cannot move as fast. I just apply the same idea as punching that relax the arm and fist to throw the punch, then tighten up at the point of contact.


Which expert?


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## Alan0354 (Nov 11, 2022)

frank raud said:


> Which expert?


You mean you are taught to squeeze the knife tight when thrusting from beginning of the thrust to the end? Doesn't make you slow down as you likely tighten the arm quite a bit if you squeeze the hand. That will really slow down the movement.

I don't remember which video, I watch quite a bit. BUT that's how punching and kicking are. You never keep everything tight, *only tighten up at the last moment*.

Like I said, I've been practicing punching on the heavy bag for many years, always relax the hand until the point of contact. BUT there are times in the midst of all the movements, I did not squeeze the fist on time when contact. It's no big deal for punching, you might not hit as hard or worst the wrist collapses, no harm no foul. BUT if you do not squeeze the knife on time while you thrust, if there is no protection, the knife will be shoved back into your hand. That would be bad.

Having a knife like this will protect you hand. The flipper tap will catch on your index finger and prevent the knife from being shoved further back even though you make a mistake.





If you have a knife like this, there's nothing to stop the knife from being shoved back into your hand:


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## Alan0354 (Nov 11, 2022)

Rich Parsons said:


> Step one:
> Buy a Beef Roast
> Step two:
> Identify a fresh washed pair of jeans you no longer want.
> ...


Ha ha, do you know how much beef cost now-a-days. The only time I cut beef is on the dinner table!!!!


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## tkdroamer (Nov 11, 2022)

Alan0354 said:


> I assume that from the start, that's why I drew a RED ring. Read post #84 again. Read the first two sentence, I already assume the force is applied evenly along the WHOLE RED ring without slack if you read my posts carefully. This is common sense!!! That's why I never follow what you said because I already spelled out loud and clear, and when you raise question, I assume it's something else.
> 
> Read post #84 again, my concern is the CRITICAL distance in GREEN between the RED circle(which you are talking about the OD of the those balls) to the edge where the blade trasition from thin to thick. If the distance is large enough, the thick part of the blade is not very helpful in strengthen it. The top drawing is very typical with the real thing on all the knives.


I think I understood most of your drawings. IF the thick part were to create come kind of shoulder that could rest against something under load, it could help. But this would negate our whole premise that the knife is a precision assembly. 
If we keep with the premise that the assembly has a tight tolerance, then the thicker section of the blade would not offer any strength. The thinnest cross section is where the blade would likely break, sans the bearing area. This is assuming the greatest load it at the pivot point. Jam the blade in a piece of wood and now you have a different lever (moment) point.


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## frank raud (Nov 11, 2022)

Alan0354 said:


> You mean you are taught to squeeze the knife tight when thrusting from beginning of the thrust to the end? Doesn't make you slow down as you likely tighten the arm quite a bit if you squeeze the hand. That will really slow down the movement.
> 
> I don't remember which video, I watch quite a bit. BUT that's how punching and kicking are. You never keep everything tight, *only tighten up at the last moment*.
> 
> ...


Aah, the unknown expert. I understand why you remain relaxed while punching, to increase speed( slightly), but that is not necessary with a knife. ANY knife has the potential to slide out of your grip, and possibly cut your fingers, if you hold it loosely. THAT'S common sense.


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## Dirty Dog (Nov 11, 2022)

Alan0354 said:


> I practice a lot in thrusting on the heavy bag, it does slip if it doesn't have that.


The knives I posted DO have that. And I have tested them (as have others) and can confirm that they are plenty deep enough to prevent the hand from sliding down onto the blade.


Alan0354 said:


> Problem is you are NOT supposed to squeeze it tight, you only squeeze on contact just like punching, you suppose to relax until you are about to contact, then you squeeze the fist.


I know how to use a blade. 


Alan0354 said:


> Problem is in the middle of everything, your timing might be off. For punching, it's no big deal, you don't hit as hard. BUT for knife, the knife can be shoved into your hand and you cut tendons and all!!! It's a chance you do NOT want to take.


I also know more about hand injuries than you ever will.
It seems clear to me that you're looking for a technological solution to a training problem.


Alan0354 said:


> I actually filed down on my first plastic knife to experiment, it did not shove all the way, BUT it did got pushed in enough it will cut my index finger if it were a real one. I had to buy a new plastic knife.


Or, as a better alternative, you could learn how to use the knife properly.


Alan0354 said:


> You ever actually thrust into a heavy bag to practice? You'll find out really fast.


Sure. And, with training blades and safety equipment, into humans. Fingers are fine. The problem, Alan, much as you typically don't want to hear it, is you. You don't know how to use the knife properly and are unwilling/unable to learn. So you insist the problem is the knife. It's not.


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## Alan0354 (Nov 11, 2022)

tkdroamer said:


> I think I understood most of your drawings. IF the thick part were to create come kind of shoulder that could rest against something under load, it could help. But this would negate our whole premise that the knife is a precision assembly.
> If we keep with the premise that the assembly has a tight tolerance, then the thicker section of the blade would not offer any strength. The thinnest cross section is where the blade would likely break, sans the bearing area. This is assuming the greatest load it at the pivot point. Jam the blade in a piece of wood and now you have a different lever (moment) point.


I like described in #84, if the critical distance is smaller like the lower diagram, the thicker part might help, but in real knife, it's quite far to be of help. That's why I raise up the concern on the first place. 

If you jam the blade in a piece of wood, that's thrusting, I don't think it's that bad even that part is thin.

Bottom line, it's NOT that hard to make that part thicker, this is proven by 3 knives I have that is plenty thick. The only reason I can think of is those people did not think deep enough. It's not rocket science if they just stop and look and think. This is not my discovery of the problem, just discovered how stupid some of them are and they call themselves designers.

Like I said, I already found my knives that is good both with ball bearings and without. More like a discussion or gripping at this point. Problem is solved for me.


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## Alan0354 (Nov 11, 2022)

frank raud said:


> Aah, the unknown expert. I understand why you remain relaxed while punching, to increase speed( slightly), but that is not necessary with a knife. ANY knife has the potential to slide out of your grip, and possibly cut your fingers, if you hold it loosely. THAT'S common sense.


Relaxing increase speed quite a bit. Same as swinging the knife from my few weeks of experience.

How can you grab the knife tight all the time  and be fast? Tell me some tricks, I am open to learn. I am confident about the physics and logic part, but I am not expert in knife fighting.

As of right now, unless I learn something different, I rather play it safe and depend on the long flipping tap to protect my hand in case I do not squeeze on time.


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## Alan0354 (Nov 11, 2022)

OK guys, You all said I don't know how to use the knife for thrusting, tell me how do you thrust so you can use those knives with very little protection and still won't get shoved back into the hand. I really want to know how. You guys must know things I don't. How do you practice to verify?


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## Dirty Dog (Nov 12, 2022)

Alan0354 said:


> OK guys, You all said I don't know how to use the knife for thrusting, tell me how do you thrust so you can use those knives with very little protection and still won't get shoved back into the hand. I really want to know how. You guys must know things I don't. How do you practice to verify?


I already told you. By cutting and thrusting. On targets. Including people. People who were doing their level best to do the same to me. And by doing so properly. By knowing that grip strength is a continuum, not an on-off switch. By not leaning from YouBoob videos.

Here's something to consider. When there are literally thousands of people who can do something, and you can't, it's probably not them. It's you.

It's not rocket surgery.


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## frank raud (Nov 12, 2022)

Alan0354 said:


> OK guys, You all said I don't know how to use the knife for thrusting, tell me how do you thrust so you can use those knives with very little protection and still won't get shoved back into the hand. I really want to know how. You guys must know things I don't. How do you practice to verify?


Stop and think. Then do it again. In subcultures known for violence, what do they carry. The traditional biker knife is a buck 110. It has nothing in the way of a guard, nothing to protect your fingers if they slide up the handle. Do you think they carry it because it is dangerous for the user? Or do they grip it hard and stab away? Even when slashing, do you think they delicately hold the knife, waiting for the last second to grip it tight? So that if their timing is off, the knife will go flying from their hand?  Or do they squeeze the knife so hard it isn't coming out of their hand on contact with a hard object?  For someone who keeps screaming about common sense, use some. Control of your weapon at all times is paramount. Your grip isn't strong enough? work on your grip.

How do you verify? Work with a partner. Work on a pell. Practice cutting and slashing on a piece of meat. When the rest of the world is concerned if the lock on their knife is strong enough to not collapse on their fingers when they stab, don't obsess over the thickness of the pivot point.


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## Alan0354 (Nov 12, 2022)

So you guys only know how to put down, can't even answer a very simple question. DO YOU SQUEEZE TIGHT ALL THE WAY, OR YOU SQUEEZE TIGHTER AT THE LAST MOMENT?

I might be new on knife, BUT I HAVE BEEN DOING KICK BOXING AND HEAVY BAG WORK FOR DECADES. I HAVE BEEN PRACTICING STICK FIGHT FOR TWO YEARS.  I always squeeze at the point of contact to gain *A LOT MORE SPEED* and be able to hold firm both the fist and the stick. Of cause it's through practice, experience and instinct, BUT, that should be emphasize from day one like my instructor.

IF YOU DISAGREE, TELL ME WHY KNIFE IS DIFFERENT FROM BARE KNUCKLE AND STICK FIGHT. I am sure NOBODY SQUEEZE THE STICK HARD ALL THE TIME. Yes, it's instinct through practice, but that's just a simple question.

Why are you people so against having an insurance. If I were you, I would think twice BEFORE use those knives without protection. *All it takes is one accident*, you likely NEVER recover from the injury. YOU WANT TO BE RIGHTEOUS OR BE SAFE. I guess I can answer this, YOU GUYS KNOW IT ALL, that I don't know anything.

I'll stay with knives with good protection no matter how good I can become in the future. It would be STUPID to say I am so good that I don't need the insurance.


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## Dirty Dog (Nov 12, 2022)

Alan0354 said:


> So you guys only know how to put down, can't even answer a very simple question.


You were given very simple answers.


Alan0354 said:


> DO YOU SQUEEZE TIGHT ALL THE WAY, OR YOU SQUEEZE TIGHTER AT THE LAST MOMENT?


Apparently, you just don't understand them. See a pattern here?


Alan0354 said:


> I might be new on knife, BUT I HAVE BEEN DOING KICK BOXING AND HEAVY BAG WORK FOR DECADES. I HAVE BEEN PRACTICING STICK FIGHT FOR TWO YEARS.


If by "DOING" and "PRACTICING" (is shouting really necessary?) you mean actual training... no, you haven't. You've been watching TV and banging away on the bag with no idea if what you're doing is correct. From what you write, it mostly isn't. But when people who really must be considered subject matter experts tell you this, you just scream and yell and stomp your feet, and cry about how mean everyone is. For all I know, you hold your breath till you turn blue as well. 


Alan0354 said:


> I always squeeze at the point of contact to gain *A LOT MORE SPEED* and be able to hold firm both the fist and the stick. Of cause it's through practice, experience and instinct, BUT, that should be emphasize from day one like my instructor.


YouBoob is not an instructor.


Alan0354 said:


> IF YOU DISAGREE, TELL ME WHY KNIFE IS DIFFERENT FROM BARE KNUCKLE AND STICK FIGHT.


Stop shouting. It's different because it's a knife. Not an empty hand. And not a stick. Much like a stick is not a katana.
Which is something else your posting history shows you do not understand.


Alan0354 said:


> I am sure NOBODY SQUEEZE THE STICK HARD ALL THE TIME.


Shouting it won't make it true. 


Alan0354 said:


> Yes, it's instinct through practice, but that's just a simple question.


And simple answers were given. 


Alan0354 said:


> Why are you people so against having an insurance.


I do have insurance. The knives I showed include quite adequate finger reliefs, and extensive testing has supported that statement.


Alan0354 said:


> If I were you, I would think twice BEFORE use those knives without protection.


That's ok. You can even think three times. People who use them already know that they're safe.


Alan0354 said:


> *All it takes is one accident*, you likely NEVER recover from the injury.


Maybe you'd be best served by never using any knife that doesn't have a "D" guard. And you should probably wear a mail gauntlet too. Possibly a full plate gauntlet, just in case you accidentally slam your hand into a concrete wall or something.


Alan0354 said:


> YOU WANT TO BE RIGHTEOUS OR BE SAFE.


Being "righteous" and being "safe" are two totally unrelated states, even when one is not shouting. I always try to be safe. Even when I do something that has inherent risks (cave diving, auto racing, sky diving, crossing the street...) I do what I can to minimize those risks.

I also try to be righteous, but I am human. And since mores differ wildly, how often I succeed is a very subjective judgement.


Alan0354 said:


> I guess I can answer this, YOU GUYS KNOW IT ALL, that I don't know anything.


Ahh, you're starting to turn blue. 


Alan0354 said:


> I'll stay with knives with good protection no matter how good I can become in the future. It would be STUPID to say I am so good that I don't need the insurance.


Do you wear a belt and suspenders at the same time? And always keep both hands gripping your pants, just in case? Maybe a pair of auxiliary suspenders?


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## jks9199 (Nov 12, 2022)

Meanwhile, I've always been taught to maintain a firm grip on any weapon.  Exactly how firm may vary along the way, but if you're not maintaining a solid grip, you're going to find your weapon on the ground at some point...

And most modern tactical knives are designed with grips and jimping or a thumb rise or other elements that reinforce the grip for the intended uses -- even if they don't have some sort of obvious guard sticking out. I'm quite confident they work, having stabbed various objects including sizeable logs with various designs.

But, you know, it seems to me that we've moved out from knife construction into knife use.  Maybe a new thread is in order?


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## Alan0354 (Nov 12, 2022)

Still can't answer a simple question. I learn this from my TKD instructor, Remember I did have a few years of formal training.


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## Alan0354 (Nov 12, 2022)

jks9199 said:


> Meanwhile, I've always been taught to maintain a firm grip on any weapon.  Exactly how firm may vary along the way, but if you're not maintaining a solid grip, you're going to find your weapon on the ground at some point...
> 
> And most modern tactical knives are designed with grips and jimping or a thumb rise or other elements that reinforce the grip for the intended uses -- even if they don't have some sort of obvious guard sticking out. I'm quite confident they work, having stabbed various objects including sizeable logs with various designs.
> 
> But, you know, it seems to me that we've moved out from knife construction into knife use.  Maybe a new thread is in order?


Yes, maintaining a grip is one thing, you don't squeeze the grip. You squeeze only at the point of contact, that should be basic and universal be it fist, stick or knife.


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## Rich Parsons (Nov 12, 2022)

Alan0354 said:


> OK guys, You all said I don't know how to use the knife for thrusting, tell me how do you thrust so you can use those knives with very little protection and still won't get shoved back into the hand. I really want to know how. You guys must know things I don't. How do you practice to verify?


 See my post about practicing on Meat and Jeans. 
If you want one can use Styrofoam (Solid) inside a Cardboard box. 
One can try different grips to see what works and doesn't work. 

You could also spend the hours posting here ( which is fine ) and drive to a real instructor. 
I drove over an hour for one of my instructors for private lessons. 
In college I drove over an hour for classes as well.  

Or are you going to ignore my comments or maybe make an off hand comment and dismay my suggestions, and continue complain we people do not engage you. 

If you ask a question and it is answered, one could acknowledge it. One could try the suggestions. One could ask for further details. 
Not just complain, and argue , and ignore and then wonder why people do not want to engage. And when they against their won better judgement do re-engage get dismissed and or YELLED at. 

One's experiences are many times a reflection of what they present to the world. 
If you are dismissive and ignoring and not willing to try to listen to people who might know more, and the big one, Actually GO FIND A REAL INSTRUCTOR even if it means scheduling a weekend away. 

So, Good Luck and I really do wish you the best. 
I just hope you understand I may not be the most informative nor contributing to your discussions .


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## Rich Parsons (Nov 12, 2022)

Alan0354 said:


> Still can't answer a simple question. I learn this from my TKD instructor, Remember I did have a few years of formal training.


You cannot answer questions posed to you.

I asked what was the actual force or use case or what have you other than a small thickness of one piece. 

Why should anyone play along with your thread when you don't respond to them.


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## Kung Fu Wang (Nov 12, 2022)

Alan0354 said:


> Yes, maintaining a grip is one thing, you don't squeeze the grip. You squeeze only at the point of contact, that should be basic and universal be it fist, stick or knife.


This dagger is better. You don't have to worry about "squeeze".


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## Dirty Dog (Nov 13, 2022)

Alan0354 said:


> Still can't answer a simple question. I learn this from my TKD instructor, Remember I did have a few years of formal training.


Simple answers given. Simple answers not understood. A couple years spread over multiple systems isn't anything.


Alan0354 said:


> Yes, maintaining a grip is one thing, you don't squeeze the grip. You squeeze only at the point of contact, that should be basic and universal be it fist, stick or knife.


And yet, acknowledged experts and practitioners of knife arts tell you different, and you persist in believing that they're all wrong. Because some guy on YouBoob said so.



Kung Fu Wang said:


> This dagger is better. You don't have to worry about "squeeze".


Illegal in many areas, and rather difficult to carry. It'll spoil the lines of your Armani.


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## Alan0354 (Nov 13, 2022)

Dirty Dog said:


> Simple answers given. Simple answers not understood. A couple years spread over multiple systems isn't anything.
> 
> And yet, acknowledged experts and practitioners of knife arts tell you different, and you persist in believing that they're all wrong. Because some guy on YouBoob said so.
> 
> ...


So just answer a very simple question, you don't agree with me to squeeze only at the last moment, so you mean you squeeze all the way from start of the movement to the end?

Just a simple question, if you just comprehend what my simple question and get over you need to put down and insult.

Simple question, you should at least have enough INTELLIGENCE to answer.


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## jks9199 (Nov 13, 2022)

Alan0354 said:


> Still can't answer a simple question. I learn this from my TKD instructor, Remember I did have a few years of formal training.


Because TKD is renowned for its knife work...

(You may wish to look into who some folks commenting here are...)


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## Dirty Dog (Nov 13, 2022)

Alan0354 said:


> So just answer a very simple question, you don't agree with me to squeeze only at the last moment, so you mean you squeeze all the way from start of the movement to the end?


I will answer it. Again. And I suspect you won't understand the answer. Again.
"Squeeze" is a meaningless word, in this context. If you don't squeeze the grip, you will drop the knife. You will never be able to pick up the knife in the first place.
Grip strength is a continuum. It's not binary. It's not either/or. It's not an On/Off switch. I've said all this multiple times, but you fail to understand it.
If you grip is loose enough that your hand can slide up the blade, then you're not doing it right. I've said this multiple times. Many others, with decades of ACTUAL training and experience in knife arts have said this multiple times. But you don't get it. So this will be the last time I say it. There is no point in discussing it further unless you somehow, after allllllll these repetitions, understand what you're being told.


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## Kung Fu Wang (Nov 13, 2022)

Alan0354 said:


> you don't squeeze the grip. You squeeze only at the point of contact,


What if when you stab your dagger at your opponent's chest, before your dagger can touch on his chest, he strikes/kicks on your elbow/wrist joint that hold the dagger?


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## Dirty Dog (Nov 13, 2022)

Kung Fu Wang said:


> What if when you stab your dagger at your opponent's chest, before your dagger can touch on his chest, he strikes/kicks on your elbow/wrist joint that hold the dagger?


Why, you will probably drop your knife, of course, if you're holding it the way @Alan0354 seems to be advocating.


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## Kung Fu Wang (Nov 13, 2022)

Dirty Dog said:


> Why, you will probably drop your knife, of course, if you're holding it the way @Alan0354 seems to be advocating.


That's my point. Dagger is the extension of your arm. You just can't afford to have a loose grip on it because you don't know when an attack can cause you to drop your dagger.


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## Dirty Dog (Nov 13, 2022)

Kung Fu Wang said:


> That's my point. Dagger is the extension of your arm. You just can't afford to have a loose grip on it because you don't know when an attack can cause you to drop your dagger.


Right. You're late to the party, but you're saying the same thing virtually every poster has said.


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## Alan0354 (Nov 13, 2022)

Dirty Dog said:


> I will answer it. Again. And I suspect you won't understand the answer. Again.
> "Squeeze" is a meaningless word, in this context. If you don't squeeze the grip, you will drop the knife. You will never be able to pick up the knife in the first place.
> Grip strength is a continuum. It's not binary. It's not either/or. It's not an On/Off switch. I've said all this multiple times, but you fail to understand it.
> If you grip is loose enough that your hand can slide up the blade, then you're not doing it right. I've said this multiple times. Many others, with decades of ACTUAL training and experience in knife arts have said this multiple times. But you don't get it. So this will be the last time I say it. There is no point in discussing it further unless you somehow, after allllllll these repetitions, understand what you're being told.


I don't think you have the intelligence to get what I said. Of cause common sense will tell you that you don't hold the knife so loose it will drop!!! You hold it tight enough to swing, then tighten further when contact. This is COMMON SENSE. How can you actually think anyone will hold the knife so loose that it will drop out? You think other people are literal like you?

Then you take the concept to relax when you swing, then tighten up when contact. Using the principle and practice and adjust.

My TKD instructor said very clearly we relax when we punch, then tighten as we contact from DAY ONE, then we practice base on that concept and work out the detail.

I guess this is just too much for you to comprehend. That you take everything literal and other people are like you!!!

Hell, when I practice stick, I intentionally do it in tight space that I accidentally hit things on the way to get use to "accidents" and still hold onto the stick even I am relax to swing. It takes practice over time to know how to how relax and squeeze. BUT THE CONCEPT IS THERE. Is this too much for you to comprehend?


So for the last time, do you squeeze tight from the start of the movement or you are more relax until the point of contact?


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## Alan0354 (Nov 13, 2022)

Dirty Dog said:


> I will answer it. Again. And I suspect you won't understand the answer. Again.
> "Squeeze" is a meaningless word, in this context. If you don't squeeze the grip, you will drop the knife. You will never be able to pick up the knife in the first place.
> Grip strength is a continuum. It's not binary. It's not either/or. It's not an On/Off switch. I've said all this multiple times, but you fail to understand it.
> If you grip is loose enough that your hand can slide up the blade, then you're not doing it right. I've said this multiple times. Many others, with decades of ACTUAL training and experience in knife arts have said this multiple times. But you don't get it. So this will be the last time I say it. There is no point in discussing it further unless you somehow, after allllllll these repetitions, understand what you're being told.


I don't know what kind of instructor you are, I can only take your word that you are. I can tell you my instructor made it very clear from day one you do NOT tighten your arm and fist, relax and only tighten up at moment of contact when we practice striking. His school is Lawler's TKD in Daly City. School is quite big with like 30 to 40 student classes. He was famous enough before he retired.

This is the concept of striking we learn, I translated to stick. I feel quite good using this with knife on bags. Like I said, *concept is simple, it's a start*. Then practice practice practice day in and day out. BUT still base on the concept.


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## tkdroamer (Nov 13, 2022)

Alan0354 said:


> I don't know what kind of instructor you are, I can only take your word that you are. I can tell you my instructor made it very clear from day one you do NOT tighten your arm and fist, relax and only tighten up at moment of contact when we practice striking. His school is Lawler's TKD in Daly City. School is quite big with like 30 to 40 student classes. He was famous enough before he retired.
> 
> This is the concept of striking we learn, I translated to stick. I feel quite good using this with knife on bags.


Let me tell you about the first thing we did in Kali training with Tuhon Bill McGrath. Starting with a 6-pound stee ball, you would drop it and then catch it over and over. Some on cadence, some on burners for 20-25 minutes. This increased to 12-pounds by the end of the year.
So, grip was not something you had to think about at some point. But to be certain, you were gripping the blade the whole time.


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## Monkey Turned Wolf (Nov 13, 2022)

Alan0354 said:


> I don't know what kind of instructor you are, I can only take your word that you are. I can tell you my instructor made it very clear from day one you do NOT tighten your arm and fist, relax and only tighten up at moment of contact when we practice striking. His school is Lawler's TKD in Daly City. School is quite big with like 30 to 40 student classes. He was famous enough before he retired.
> 
> This is the concept of striking we learn, I translated to stick. I feel quite good using this with knife on bags. Like I said, *concept is simple, it's a start*. Then practice practice practice day in and day out. BUT still base on the concept.


You can keep a loose shoulder and still have a tight grip on a weapon. And knives and open-handed are two very different beasts, in large part for the difference wang mentioned a few posts up.


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## Rich Parsons (Nov 13, 2022)

Monkey Turned Wolf said:


> You can keep a loose shoulder and still have a tight grip on a weapon. And knives and open-handed are two very different beasts, in large part for the difference wang mentioned a few posts up.


You mean the attributes of the weapon affects the technique  
No way.


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## Kung Fu Wang (Nov 13, 2022)

Rich Parsons said:


> You mean the attributes of the weapon affects the technique
> No way.


There is a good reason that ancient "under water weapon" has a loop on the handle. This way when you swim, even if you may have loose grip, you won't drop your weapon.


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## Alan0354 (Nov 13, 2022)

tkdroamer said:


> Let me tell you about the first thing we did in Kali training with Tuhon Bill McGrath. Starting with a 6-pound stee ball, you would drop it and then catch it over and over. Some on cadence, some on burners for 20-25 minutes. This increased to 12-pounds by the end of the year.
> So, grip was not something you had to think about at some point. But to be certain, you were gripping the blade the whole time.


We never even get to any of the exercise, I never said grip is not important. In fact, I spend 1/2hr each week just on grip exercise, might not be what you do, but I use grippers and wrist exerciser. I am quite sure my grip is NOT weak compare to the rest of my body. This is common sense, when doing stick fight or knife weapon etc, grip strength is very important and I put a lot of emphasis on grip exercise.

BUT, that's not the big argument here. I know the answer already. You relax the shoulder and arm, you hold the knife secure enough to swing and thrust. But you grip harder when contact. This is just COMMON SENSE, I'm not here to learn how to walk!!! Using this concept, practice practice practice to get the feel when to relax, how much to relax and still hold onto the knife, when to tighten to get the best effect. Just like punching and stick fight. Who is SO STUPID, to relax all the way and let things fry out of the hand?

BUT Dirty Dog came out and kept saying WRONG WRONG WRONG without even trying to ask a single question. He ONLY KNOW HOW TO PUT DOWN. He can't even answer a SIMPLE question, if it is WRONG to relax in the swing and tighten up at contact, WHAT IS THE RIGHT WAY. He can't even answer. There goes round and round of insult!!!

Some people here are *SLOW*!!! We don't know how good HIS MA skill, we can only take his words. But I hate to say from* this post*, some are SLOW. *AND they assume without even clarify, *just going around and around and around. Read the whole thread if you care, from talking mechanical theory to this, how many times I have to keep going over and over and over and over. People don't read and jumped to conclusion and come out with big statements..........


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## Alan0354 (Nov 13, 2022)

Monkey Turned Wolf said:


> You can keep a loose shoulder and still have a tight grip on a weapon. And knives and open-handed are two very different beasts, in large part for the difference wang mentioned a few posts up.


YES, this is common sense. Maybe I should clarify a little more, but for cry out loud, people really take it LITERALLY that relax the hand to the point the weapon flies off the hand when swinging? WOW, like talking to a child?

Even if someone said something one consider strange and crazy, at least take the time to clarify before jumping to conclusion.

I really learn a lot in this thread, really a lot!!! WOW!!! From simple common sense mechanical to just such basic stuff of holding a weapon.....WOW.

I know I am not making friends here, I might be banned, but WOW!!!! I was debating whether I post here or Physics Forums that I used to frequent as contributor. I should have gone there even though they have no interest on knives. Discussion would have been ended in a day or so.

I think this post should be LOCKED. Nothing to talk anymore, BOTH mechanical design and fighting skill. BUT I did learn A LOT........... Not on the subject of the thread!!!


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## drop bear (Nov 14, 2022)

Alan0354 said:


> I don't remember which video, I watch quite a bit. BUT that's how punching and kicking are. You never keep everything tight, *only tighten up at the last moment*.



If you get a rubber knife and spar like that. You will find it has a tendency to pop out of your hand in the kaos. I found even being a bit lazy with the grip can make you loose the knife.

Especially if they are doing hard blocks.


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## drop bear (Nov 14, 2022)

Alan0354 said:


> I'll stay with knives with good protection no matter how good I can become in the future. It would be STUPID to say I am so good that I don't need the insurance.


A decent handle you can grip is very important.i am not sure why you are getting so much resistance to that.

I tried flicking open my sr1. Look it's doable.





And that would give you the closest you will get to a prybar that probably won't come out of your hand.

The lite version is a bit cheaper. And should do fine for what you want.

Here we go.





The guy pops it open. And from just eyeballing there is quite a bit of steel in the bit you want a bit of steel to be.


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## Monkey Turned Wolf (Nov 14, 2022)

Alan0354 said:


> YES, this is common sense. Maybe I should clarify a little more, but for cry out loud, people really take it LITERALLY that relax the hand to the point the weapon flies off the hand when swinging? WOW, like talking to a child?
> 
> Even if someone said something one consider strange and crazy, at least take the time to clarify before jumping to conclusion.


So clarify. Are you suggesting holding it loosely or not? I'm not referring to it flying out when swinging (though that is certainly possible and has happened to most people who keep a loose grip at some point), but just holding it generally loosely lets it get knocked out easier from unexpected force on it.


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## Dirty Dog (Nov 14, 2022)

Monkey Turned Wolf said:


> You can keep a loose shoulder and still have a tight grip on a weapon. And knives and open-handed are two very different beasts, in large part for the difference wang mentioned a few posts up.


You mean to say it's not an either/or binary thing????? That's insane!


Rich Parsons said:


> You mean the attributes of the weapon affects the technique
> No way.


Shocking.


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## Alan0354 (Nov 14, 2022)

drop bear said:


> A decent handle you can grip is very important.i am not sure why you are getting so much resistance to that.
> 
> I tried flicking open my sr1. Look it's doable.
> 
> ...


Cold steel is good, notice they don't use ball bearings and pivot area is very robust? Notice if you look deeper into those torture videos, a lot of knives they use were without ball bearings. That MIGHT give a miss-conception that the pivot is never a problem.

I am not even saying the pivot area is the most critical, it's just going down the list of finding all the potential weak point and avoid it.

Yes, the ones with longer flipper tab offer better protection and serve as insurance. Why fight it.


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## Alan0354 (Nov 14, 2022)

Monkey Turned Wolf said:


> So clarify. Are you suggesting holding it loosely or not? I'm not referring to it flying out when swinging (though that is certainly possible and has happened to most people who keep a loose grip at some point), but just holding it generally loosely lets it get knocked out easier from unexpected force on it.


What I do is before I start swinging or thrusting, I hold it loose enough, when I start to swing or thrust forward, I slowly tighten the grip, but not enough to make me tighten my shoulder and arm, then tighten up right before contact so I get full grip when contact.

Like I said, holding it loosely and tighten when contact is the *CONCEPT to practice.* You practice and practice and slowly get the timing down. It takes time to go from loose to tight, the amount of time to go from start to contact. So at the end, it's a continuous motion.


*BUT the concept is very important from day one and practice*. Then you adapt to the best way somewhere in the middle.



For me, I also practice to have accidental contact along the way with my stick fight. I intentionally practice swinging in tight space with things in the way. I practice so I don't lose my cane if I contact something along the way when I am not in full grip strength. I even have fast moving target that with the best effort, I would miss to make sure I don't lose my cane.

It's a concept to relax before contact and grip at contact, but you practice in all different situation until you don't lose your cane/knife in all different situation.


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## drop bear (Nov 14, 2022)

Alan0354 said:


> Cold steel is good, notice they don't use ball bearings and pivot area is very robust? Notice if you look deeper into those torture videos, a lot of knives they use were without ball bearings. That MIGHT give a miss-conception that the pivot is never a problem.
> 
> I am not even saying the pivot area is the most critical, it's just going down the list of finding all the potential weak point and avoid it.
> 
> Yes, the ones with longer flipper tab offer better protection and serve as insurance. Why fight it.



For flippers. Have you considered the Crawford






That must be a new video. They seem to be actively shying away from saying how good their knives are for murdering people.

Crawford traditionally does defensive knives. It is designed for pretty much that job.


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## Alan0354 (Nov 14, 2022)

drop bear said:


> For flippers. Have you considered the Crawford
> 
> 
> 
> ...


Yes, seriously looked into it. Now this is my own crazy issue. I don't know why I love plastic polymer guns, but I don't like polymer only knife handle!!! One side of the handle has no steel lining. That's the ONLY reason I didn't go for it. I know, this is my problem!!! Here's the video:





Actually I found what I want, I am not even looking much lately. This is my go to knife I carry all over with me. The Steel Will Warbot. I bought two of this:
Warbot

It's hefty 6oz. I opened it and took pictures. Look at the inside:




The two side plate is 0.06" thick, not ball bearings, thick blade.......This is every bit as robust as Cold Steel. I really sharpened it. 

I might still buy the Crawford 1 in the future if I can get over the plastic part of it.

Thanks


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## Alan0354 (Nov 14, 2022)

drop bear said:


> A decent handle you can grip is very important.i am not sure *why you are getting so much resistance to that.*
> 
> I tried flicking open my sr1. Look it's doable.
> 
> ...


I am stunned too.

I join two other knife forums and read some of the comments. Knives to them are like handbags to women. It's about NAME brands, nice looking, a lot of them are thin and trim looking. Even the more rugged looking ones don't have the protection. Look at Spyderco, expensive, but look at this:




There is NO protection of your hand.

A lot of other expensive ones are thin and trim looking, like for dress ups. this is one of the example of $200 knife, very little protection:
KUBEY New Dandy KB247

I have slim ones too, but I still get with flipper tap. These are two I have, big one is Kizer, the small one is Carimee. Kizer was $69 which I got for 1/2 price on one day sale on Amazon, the other one was on sale too.







they are slim, but still have good protection.

No matter how good one in using knife as weapon, it never hurts to have *INSURANCE*. In the middle of the fight, all it takes is a moment lose of concentration and forget to hold the knife tight, the knife gets shoved back and one will have to have multiple surgeries and long time to repair the hand.

But I notice, it's no use talking to those people. *They can't hear you.* They only look at how much it *cost*, what *brand*. Everyone kept telling me cheap knives are all junk. I can tell you, other than the *Steel Will Warbot* I have the built like a tank, my next knife that I feel most comfortable and sturdy is one that cost $26. That's AFTER I opened it up, looked at everything and still think it's the second toughest knife in my collection. The bottom knife in the picture below is the *LAURISLVA *medium size. The top one is Steel Will Warbot which I have two.





Surprisingly, the steel plate on both sides are *0.06"* thick, it has ball bearings. But the few I got is at least* 0.05"* thick on the critical part of the pivot point as described in detail in this thread. The only problem that I do not out right recommend this is because the thickness vary with different knives(of the same model). Maybe it's of *different runs in production.* I have to buy, open up to measure to determine whether I keep it or return it. But when it is good, it's really good.

Ha ha, for $26, I already bought 4, enough for the rest of my life, still it's only $100!!!


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