Do knives have torque ratings for their steels?

[David Mary]

"Someone needs my help!"

 

[knarfeng]

I cant find anything but was wondering if blades have a torque rating? Like how much pressure can they withstand sideways before they break? Yes I know never pry with a knife and I dont but I think some sort of rating on this would be good information to have. Maybe the info is out there and I just dont know where to look?

Well when using a knife heavily on a boat or farm sometimes things happen. I think knowing how much torque a knife blade can handle would be good information.

Well thick wet crab lines can pull and tighten when you least expect it and has caused sideways torque on my knives. Its not something that happens often but it happens. Ive been shaving down 2×4s with light batoning and had the knife blade slip and go sideways on me. Just some examples.

"Torque" is a rotational force, not a sideways force. So unless you are burying the blade iin a fish, then rotating the knife, "torque" is not what you are talking about.

You know there is a sticky that leads to an article on Larin's Knife Steel Nerds site.

Thread 'I Tested the Edge Retention of 48 Steels'

May 1, 2020

Recently I was able to acquire a used CATRA machine, so I heat treated just about every knife steel I had, made 57 knives with the help of knifemaker Shawn Houston, and tested them all to see which cut the longest. For a few of the steels I did multiple heat treatments to look at a couple variables and to see the effect of hardness. I also compared edge retention and toughness to see which steels have the best balance of properties. https://knifesteelnerds.com/2020/05/01/testing-the-edge-retention-of-48-knife-steels/

• Larrin
• Replies: 680
• Forum: General Knife Discussion

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in that article Larin measures toughness using a Charpy test, and he generated graphs and charts of steels rated for toughness and comparing them to the edge retention. Those Charpy results give you the information you want. I would recommend that you go read that article written by a PhD Metallurgist who has a knack for making complex topics accessible to those of us with less complex minds.

 

[Synov]

You want high toughness and hardness, so steels at the top right of this chart. AEB-L and 14C28N are easy to get.

 

[shqxk]

Most of the time, when we’re cutting something “hard,” we’re applying literal force to a very small portion of the edge apex, and each steel has different durability in this regard.

Larrin did a video on his YouTube channel about bending strength, which should be directly related to this subject.

 

[ShaiHulud]

A Becker BK3 can probably handle a lot of oblique torque because its secretly a digging bar

 

[David Mary]

More accurately, we are concentrating force through the apex, not applying force to it.

 

[Delgadonine]

I cant find anything but was wondering if blades have a torque rating? Like how much pressure can they withstand sideways before they break? Yes I know never pry with a knife and I dont but I think some sort of rating on this would be good information to have. Maybe the info is out there and I just dont know where to look?

Im sure no such rating exists.

Crowbars, Hammers, Screwdrivers do not have such a rating system.

If I were to rate this process, I would look at Human strength.

Who can curl or benchpress more than me?

A lot of you, certainly...

 

[DMG]

The funny thing is that the chart posted above is indeed torque ratings for knives, measured in ft/lbs.

 

[hugofeynman]

My favorite "torque knife steel" tester:

Here, he is "torque testing" this knife made in one of my favorite steels, 50crv4/6150. That thing survived everything Joe threw at it, shotgun and 9mm Glock included.

 

[pease]

I cant find anything but was wondering if blades have a torque rating? Like how much pressure can they withstand sideways before they break? Yes I know never pry with a knife and I dont but I think some sort of rating on this would be good information to have. Maybe the info is out there and I just dont know where to look?

How are you going to connect the knife to a torque wrench? I’ve never seen a 1/4 square hole on a knife.

 

[Eliteone2383]

How are you going to connect the knife to a torque wrench? I’ve never seen a 1/4 square hole on a knife.

Yeah my terminology is obviously off.

 

[Seedy Lot]

How are you going to connect the knife to a torque wrench? I’ve never seen a 1/4 square hole on a knife.

I made a metal adapter with a slot in it so I could use a torque wrench to compare how much force it took to break different steels in bend to break.

80crv2 hands down was the champ. From my testing the higher the carbide volume the easier a steel is to break when prying.

 

[Taz]

That makes sense. Larger carbides can make the steel more brittle, like having a larger overall grain. I believe there was a good bump in toughness in D2 and CM154 in the CPM Powder Metal versions due to the smaller carbide size. Simple carbon steels and stuff like AEB-L/NitroV/14C28N are usually pretty tough due to lower carbide volume and tiny carbide size.

I use the chocolate chip cookie example often. Micro chips, cookie holds together. Normal chips, not too bad. Using Big Chocolate chunks means the cookie falls apart MUCH easier. Same recipe, different size "carbides/chocolate chips".

 

[Arathol]

"Torque" is a rotational force, not a sideways force. So unless you are burying the blade iin a fish, then rotating the knife, "torque" is not what you are talking about.

I'm not so sure......When you stick a blade in a stump and try to pry it out (a fairly common youtube test for tip integrity) you are exerting a rotational force on the blade.

This should be pretty easy to measure using a torque wrench, preferably digital that records peak torque, and a thick wall impact socket with a slot cut in it. You could in theory do a torque to yield test to find out what it takes to bend a blade past the point of reversible elastic deformation (bending and returning without damage) and how much force its takes to actually break the blade.
Of course, this is mostly irrelevant without some sort of standards or baseline for comparison...

 

[Taz]

Grind (flat, convex, hollow ground), Geometry (thin or thick grinds) and lots of factors come into play. We also need to assume heat treating is done to have a fine grain structure to start. A steel at 62 rockwell can have super fine grain, or coarse, chunky grain, even though it's the same steel. More or less retained austenite can change the results, too!

IIRC, Larrins recent article explained a lot of these factors? https://knifesteelnerds.com/2025/11/12/knife-broke-with-cpm-3v-isnt-it-a-tough-steel-qa-video/

 

[hugofeynman]

Grind (flat, convex, hollow ground), Geometry (thin or thick grinds) and lots of factors come into play. We also need to assume heat treating is done to have a fine grain structure to start. A steel at 62 rockwell can have super fine grain, or coarse, chunky grain, even though it's the same steel. More or less retained austenite can change the results, too!

IIRC, Larrins recent article explained a lot of these factors? https://knifesteelnerds.com/2025/11/12/knife-broke-with-cpm-3v-isnt-it-a-tough-steel-qa-video/

So, asking someone to heat treat a specific type of steel to a specific Rockwell hardness means sh#t! Microstructure is king!!!!!

 

[David Mary]

Microstructure matters a lot, but saying target hardness means nothing isn’t true. Hardness defines the performance window and what microstructures are even possible. Two blades at 62 HRC can differ in quality, but a good 62 HRC blade is still very different from a good 57 HRC blade. Microstructure tunes the result; hardness sets the limits.

 

[knarfeng]

I'm not so sure......When you stick a blade in a stump and try to pry it out (a fairly common youtube test for tip integrity) you are exerting a rotational force on the blade.

This should be pretty easy to measure using a torque wrench, preferably digital that records peak torque, and a thick wall impact socket with a slot cut in it. You could in theory do a torque to yield test to find out what it takes to bend a blade past the point of reversible elastic deformation (bending and returning without damage) and how much force its takes to actually break the blade.
Of course, this is mostly irrelevant without some sort of standards or baseline for comparison...

It's not clear to me that is actually measuring torque, per se. But if you did such a bend test, I think the test specimens would all need to be dimensionally identical in order to make a valid comparison between steels. So I think you would need to test a complete set of flat bars, all the same, with exactly the same hold point and pressure application point. And I have no idea what you'd need to do about Rockwell.

BTW, Cold Steel actually did that sort of blade bending in some of their fixed blade videos. No comparisons between steels, but they stuck the tip of the blade in a vise and pulled sideways on the handle.