Benchmade Vex: another not-quite-right cheap knife

[kel_aa]

point about the torque advantage of the hole in regards to position relative to the pivot.

I'm not sure it is purely about torque as per torque arm. I'd suggest it is more of a grip security issue and biomechanical issue. Biomechanical as in the thumb cannot provide force equally in all positions (like you cannot provide the same torque to a crank throughout its full rotation). Grip security as in the secureness of your grip changes with relative thumb position and thumb force.

 

[stevetexas]

Hi Y'all,

I have been wondering about the steel type and hardness figures on some of the China knives. Some are now saying they are 440c instead of a, and hardness figures quoted are harder than in the past, while retaining the same price point.

Did somebody in China find out that it is easy to lie about the steel and/or hardness in order to boost sales? Or have they truely upgraded the products?

Ink on adverts is cheap. Upgrades to products are expensive.

Steve

 

[Carl64]

Spyderco's Byrd's were said to be around 60rc, and they feel like it.

Benchmade only claimed the Vex to be 56-58, and it is appropriately mediocre.

 

[gunmike1]

Spyderco's Byrd's were said to be around 60rc, and they feel like it.

Benchmade only claimed the Vex to be 56-58, and it is appropriately mediocre.

So you haven't been happy with the Vex steel compared to the Byrds? I like the Byrd steel a lot, price point be damned. It takes a really sharp edge and sharpens pretty easily, and is reported to be at 61 HRC. When I saw how soft Benchmade was running the Vex I thought it might lead to worse performance than the Byrds, but you never know until you use them, or even what they are actually hardened to. I handled a Vex in a store and it was pretty boxy feeling to me, though the fit and finish looked good.

 

[Carl64]

So you haven't been happy with the Vex steel compared to the Byrds? I like the Byrd steel a lot, price point be damned. It takes a really sharp edge and sharpens pretty easily, and is reported to be at 61 HRC. When I saw how soft Benchmade was running the Vex I thought it might lead to worse performance than the Byrds, but you never know until you use them, or even what they are actually hardened to. I handled a Vex in a store and it was pretty boxy feeling to me, though the fit and finish looked good.

The blade is thicker, so a fair comparison of cutting is not easy. But for sharpening, the Vex hangs onto its burr. When it was new it was sharp enough. Edge retention wasn't horrible, but sharpening could go better.

The Meadowlark is better for both edge retention and sharpening.

 

[James Y]

Being a fan of both BM and Spyderco, I've watched and waited on their China-made offerings, because I've been skeptical. Though I think the Vex looks nice, I think for my first China-made knife I will probably try a Byrd Cara-Cara. The Byrds have gained an acceptence/popularity due to good performance.
Jim

 

[gunmike1]

The blade is thicker, so a fair comparison of cutting is not easy. But for sharpening, the Vex hangs onto its burr. When it was new it was sharp enough. Edge retention wasn't horrible, but sharpening could go better.

The Meadowlark is better for both edge retention and sharpening.

The burring is the main issue I was afraid of. My soft CRKT's (AUS-6 & 8) are burr mongers, so I have come to really hate a soft steel for sharpening.

 

[Cliff Stamp]

But for sharpening, the Vex hangs onto its burr.

... so I have come to really hate a soft steel for sharpening.

Just quoting to quote as I have been pushing for this acceptance for about 10 years now and away from the common myth that edge retention and ease of sharpening are directly in opposition.

-Cliff

 

[HoB]

You know, Cliff, that I totally agree, that ease of sharpening and edge retention are not exact opposites. But I am not sure whether it is really the steel's softness that creates these burrs. I just finished sharpening two axes and even though they are a bit softer than your average knife, I didn't have much of a burr problem. I think it is mainly the soft stainless steels that feel like rubber on the stone.

 

[Carl64]

But I am not sure whether it is really the steel's softness that creates these burrs. I just finished sharpening two axes and even though they are a bit softer than your average knife, I didn't have much of a burr problem. I think it is mainly the soft stainless steels that feel like rubber on the stone.

If the axe is Carbon steel, it has lower resistance to wear (like from a sharpening stone) than Chromium-packed stainless. Steel that wears down easier, such as from not having as much Chromium, can be softer without having burr issues.

Stainless steels are more likely to be a problem because they are loaded with a lot of Chromium, among other elements. It's necessary to make it stainless, but "wear resistance" is often a goal. Manufacturers like to talk about it today, even though it's probably the last thing most steels are lacking.

Of course if you sharpen an axe at a steeper angle than a knife, that also reduces burring.

 

[HoB]

Well, quite frankly, it is not entirely clear to me, what is going on when a steel burrs badly. The larger the amount of carbide formers in the steel, the less "flesh" to support the carbides which should subsequently break out more easily and hence form LESS of a burr. My suspicion is actually that the burring is more dependent on the amount of FREE Chromium which really doesn't add much to wear resistance if I am not mistaken. But this is all just a theory formed from experience. The worst burrs I am usually getting on the really cheap cutlery stainless steels, or a steel like 420 which aren't that abrasion resistant.

True on the axe angle, but then again the terminal angle I try to put on an axe is right around 20 deg. per side, which is larger than my knives, but right around what many factory geometries would be.

 

[Carl64]

My suspicion is actually that the burring is more dependent on the amount of FREE Chromium

Yeah, that's what the more chemistry-endowed people tell me. Along with the fact that no single element is usually the only one to affect a single characteristic.

Chromium is used in most "tool steels" for reasons other than rust resistance, and the total effect of Chromium can be misleading without knowing all of the other additives, so any statement about one ingredient is very general.

But the level of Chromium used for non-stainless tool steels that don't need to be "stainless" is usually something like 1-5% with a few exceptions, if even that much. Most stainless steels have 14 or 15%, so I guessed most of them end up in the category of steels with a lot more Chromium than they need for reasons other than rust resistance, and carry an excess of any other Chromium characteristics, assuming all else remains the same.

which really doesn't add much to wear resistance if I am not mistaken.

There are other things in the steel which add both rust resistance and wear resistance. I don't know how much wear resistance Chromium provides compared to other elements also used, but it's usually listed with that as a benefit.

The worst burrs I am usually getting on the really cheap cutlery stainless steels, or a steel like 420 which aren't that abrasion resistant.

I don't know the exact wear resistance of 420 (whichever version we might be looking at) compared to 440c, but at the same time I do know that 420j2 is often made much softer than anything else. CRKT does it at 54-56. I forget which brand listed it as 52. Who knows what a cheap kitchen knife is. Even with less wear resistance, we could be looking at something ridiculously soft.

Note that I do NOT disagree that the other things like grain also play a part in making sharpening miserable. But I do think that a soft steel which does not want to get ground away is a good formula for a bad sharpening.

True on the axe angle, but then again the terminal angle I try to put on an axe is right around 20 deg. per side, which is larger than my knives, but right around what many factory geometries would be.

Spyderco's Sharpmaker uses 40 degrees total on the wide setting. if it's sharp enough for a knife, it's sharp enough for an axe.

That's the final edge angle I usually use (double bevel near the edge) and it's the same angle the Vex has been slightly ornery at. It's not a useless edge at all, but noticable enough that I think "if the Byrd doesn't do this, why should the Vex?"

 

[Cliff Stamp]

But I am not sure whether it is really the steel's softness that creates these burrs.

It is a combination of factors, strength, grindability, grain/carbide size, etc. . Soft carbon steels have a high grindability, with almost no carbide fraction and thus they sharpen well even when soft.

-Cliff

 

[phatch]

After reading this thread, I took my Vex and sliced up a bunch of cardboard boxes. I sharpened it earlier this week without any burr trouble and it's been unused since. But I'm a stropper so that tends to minimize the burr issues in my experience.

It slivered the few boxes I had on hand just fine and was still plenty sharp at the finish. I don't shave test as I have super fine arm hair that defies shaving generally. What will shave my local knife knuts hair won't shave mine.

I agree, the Vex's steel is softer than AUS 8. I've always felt AUS 8 was on the hard side to sharpen compared to 440C, ATS34 and such. But I think The vex steel holds the edge better than AUS 8 in my experience so far.

Phil

 

[Sal Glesser]

It is a combination of factors, strength, grindability, grain/carbide size, etc. . Soft carbon steels have a high grindability, with almost no carbide fraction and thus they sharpen well even when soft.

-Cliff

We had a burr problem with S90V. The burr just "hung on". Sharpening on a belt. Rc was about 59.

sal

 

[HoB]

That is really interesting. I wonder how the carbides can break out so easily out of the matrix as Landes claims on the high carbide fraction steel, yet a burr won't break off. You would expect the burr to simply crumble.

If I understand grindability is low on high carbide steels because the "teeth" (carbides) are very hard and are supported in the matrix, pertaining mainly to geometries in which enough meat is left to support the teeth. In a burr there is *no* meat left to support the carbides and the burr should simply fall apart.

Obviously it is a combination of factors and I agree that Chromium is not likely the only one, but really the question is what that combination is and what the main contributing factors are. Hardness alone is clearly not.

 

[Carl64]

The burr can contain many molecules (both meat and teeth) which have never seen the sharpener.

You don't actually want anything to break off, even though people often speak of "breaking off the burr." When pieces break off, you get chunky and blunt surfaces. At a microscopic level the act of grinding steel down could probably be described as breaking small pieces off, but not burr-sized pieces.

If that steel had not bent over, much of it would have ground off (if not already, eventually).

 

[HoB]

Well, I didn't say breaking off, I said crumbling. My point was more that a burr is usually thinner than the smallest edge geometry that the high carbide volume steels seem to be able to support. So if a thin edge from these high carbide volume steels crumbles, I think you would expect to see the same behaviour on a burr, instead of being able to support a stubborn and cohesive burr structure?

 

[Carl64]

Well, I didn't say breaking off, I said crumbling.

Gotcha. Misquoting was not intended. Like crumbling as it is sharpened, before it actually forms a burr you would notice?

My point was more that a burr is usually thinner than the smallest edge geometry that the high carbide volume steels seem to be able to support. So if a thin edge from these high carbide volume steels crumbles, I think you would expect to see the same behaviour on a burr, instead of being able to support a stubborn and cohesive burr structure?

I think the thinness might actually make it more able to flex without...separating?

I was thinking we were looking at two opposites. An adequately-hard edge might suffer from crumbling due to the carbides, but not burring, while a softer steel will have more [ductility?] to avoid crumbling, but then be subject to burring.

 

[Cliff Stamp]

We had a burr problem with S90V. The burr just "hung on". Sharpening on a belt. Rc was about 59.

Grindability/carbide density is far too low for that hardness.

I wonder how the carbides can break out so easily out of the matrix as Landes claims on the high carbide fraction steel ...

Landes doesn't claim it, he directly measured it and photographed it. There is also a huge body of research done in this area by the steel companies that actually focus on knife steels.

In a burr there is *no* meat left to support the carbides and the burr should simply fall apart.

Not exactly. If you look at burrs under high mag you can see they are very jagged, often highly irregular. They are deformed to plastic and just barely holding on, which is why you can easily scrape them off with your finger nail.

The reason why burrs tend to form on soft but low grindability steels is that those steels need a lot of force to abrade but have little ability to resist the force and thus they deform without getting cut.

There are other issues like inherent fracture, carbide tearout, inconsistent structure, etc. .

I think the thinness might actually make it more able to flex without...separating?

In general yes. The thinner the steel the lower the strain at a given flex.

-Cliff