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

[Alan0354]

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

 

[Alan0354]

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.

 

[Dirty Dog]

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.

 

[Alan0354]

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.

 

[wab25]

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.

 

[tkdroamer]

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:

View attachment 29162
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:
View attachment 29163

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
View attachment 29164

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

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.

 

[Dirty Dog]

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.

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.

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.

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.

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.

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.

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.

 

[Alan0354]

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.

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.

 

[drop bear]

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.

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

 

[Alan0354]

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.

 

[Alan0354]

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.

 

[Alan0354]

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!!!

 

[wab25]

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?

 

[Alan0354]

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.

 

[wab25]

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?

 

[Alan0354]

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.

 

[Alan0354]

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.

 

[Wing Woo Gar]

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.

 

[Wing Woo Gar]

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

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.
View attachment 29166
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!!!!

View attachment 29167

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

 

[Alan0354]

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