154CM or M2

Danbo · Mar 13, 2001

Well, I see we have some kind of censor on this site. All I did was type in the name of a very popular sharpening stone, and it edited my message because SOMEBODY thought part of the name was an obscenity. Wazzup wit dat?

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Danbo, soul brother of Rambo

OwenM · Mar 13, 2001

Joe,
I was not aware that BMs 154CM was softer than their ATS-34. I usually group them together in my thinking. The knives I have used most are ATS-34. The only 154CM blade I use is on a BM 940 (not my idea of a heavy duty work knife).
I would think that 154CM being softer would make it less prone to chipping, not more, and give it less wear resistance.
Regardless, when you're making a tough cut, and the knife comes loose (whether from going completely through the material being cut and still having pressure on it, or from cutting up against something in an awkward position), and bangs into steel or concrete, something has to give. When this happens with significant force, my ATS chips, my M2 rolls.
I don't know what kind of cardboard you're cutting, but I cut 1/4", 1/2" and 3/4" cardboard regularly. It is generally full of abrasive grit (I have not noted "significant edge degradation" with ATS-34 or M2 except when cutting very large amounts, and haven't noticed a big difference btw the two). Lots of industrial air/water hose, thick paper and plastic sheeting, plastic straps, and occasionally bags full of abrasive material (it's used in brake pads) that we produce and sometimes have to rework, too.
I'm not basing my opinion on tests, but on use.
One thing that may affect my perception of M2's edge-holding is that I use more force when cutting with the 710HS because it is an Axis lock, and I have more confidence in the lock and overall strength.
I wonder how much difference that makes? Cutting the same materials, only faster and harder. Something I've thought about before.

[This message has been edited by OwenM (edited 03-13-2001).]

Joe Talmadge · Mar 13, 2001

Originally posted by OwenM:
Joe,
I was not aware that BMs 154CM was softer than their ATS-34. I usually group them together in my thinking. The knives I have used most are ATS-34.

Hey Owen,

Actually, it's just a theory, but it seems as if Benchmade backed off a bit on their ATS-34, and I'm assuming they're doing the same on their 154-CM. Actually, it's not just a theory. I notice my newer 710, with 15-degree bevels, does not chip under circumstances that my old AFCK would chip when sharpened at 15-degrees with a heavy 20-degree double-grind over it. Plus, there is a gun on the Benchmade forum who has been rockwell testing Benchmades, and as I recall he's seeing more like 59 and 60 numbers now. Anyway, this hasn't been confirmed by Benchmade, but I'm pretty sure they've backed off just a tad, aiming for the low-end of their advertised 59-61 Rc range.

Regardless, when you're making a tough cut, and the knife comes loose (whether from going completely through the material being cut and still having pressure on it, or from cutting up against something in an awkward position), and bangs into steel or concrete, something has to give. When this happens, with significant force my ATS chips, my M2 rolls.

Gotcha. That makes sense. What I'm suggesting is that at lesser pressures, there are cases where the ATS-34 will still chip but you won't see much if any rolling in the M-2. And for micro-chipping, you'll see even less effect on the M-2 when the ATS-34 is getting little bumps.

I don't know what kind of cardboard you're cutting, but I cut 1/4", 1/2" and 3/4" cardboard regularly. It is generally full of abrasive grit (I have not noted "significant edge degradation" with ATS-34 or M2 except when cutting very large amounts). Lots of industrial air/water hose, thick paper and plastic sheeting, plastic straps, and occasionally bags full of abrasive material (it's used in brake pads) that we produce and sometimes have to rework, too.
I'm not basing my opinion on tests, but on use.

I tend to rely on both tests and use. Use is obviously the real determiner, but I always wonder if I'm using both knives exactly the same way, or if a subjective impression I have is affecting my perception of performance. And you bring up a really good point below, where confidence in the lock might be affecting how hard you use one knife versus the other. As a result I like to factor in more-controlled tests as well. I can't fault you for relying on your own experience, obviously, if that's what you've seen, that's what you've seen! It's a data point that's different from mine but nevertheless just as valid, that mjoury should consider.

One thing that may affect my perception of M2's edge-holding is that I use more force when cutting with the 710HS because it is an Axis lock, and I have more confidence in the lock and overall strength.
I wonder how much difference that makes? Something I've thought about before.

That's interesting. I'm affected by exactly the same thing. The confidence in the lock definitely inspires harder use, which in turn affects results in real use.

Joe

dogboye · Mar 13, 2001

If you are going to be cutting carpet (lots of grit), plastic planters (lots of grit), or cardboard (lots of grit, and my personal favorite testing medium), you want M2. The only steel that I have found that will best M2 with any significance at all in edge holding isn't a steel at all, but cobalt alloy: Talonite. In a similar edge length, albeit different grinds (M2 Nimravus Cub vs. CUDA Talon), the two went neck and neck, and I could NOT determine a single inch difference in amount of cardboard cut, with both still being able to shave when I ran out of cardboard. Both went through about 30 feet (26 slices at about 14 inches each) of corrugated cardboard and were still shaving, fairly cleanly. I wasn't able to get either to stop shaving with the amount of cardboard I had. By comparison, my 440V Military definitely gave up shaving about 5 feet shorter.

Now, comparing less rigorously how 154CM or ATS-34 degrade in similar cardboard cutting, they BOTH have significantly less edge holding than M2. D2 and BG42 are the only others that I have and tried, that seem to be anywhere near up to M2 and Talonite.

I like 154CM, but if I were given a choice between it and M2 for a given design (BM 710), I'd get the M2, if I really planned on using it hard.

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The most affectionate creature in the world is a wet dog. - Ambrose Bierce
Most dog owners are at length able to teach themselves to obey their dog. - Robert Morley

iktomi

[This message has been edited by rockspyder (edited 03-13-2001).]

Bertrand · Mar 13, 2001

Just to add a little info, a while back I tested the hardness of a few blades. A 710 and a 721, both in ATS-34, were 59 Rc. A 940 in 154CM was 60 Rc. Guess I'll have to test my 690 to see if BM has "softened" up their 154CM...

Russ

The General · Mar 13, 2001

Owen while normaly I would agree that mr Mayo knows a lot more about this than me, in this case I am mearly giving my mileage on this question. As that is what we are talking about allow me to tell you something...

I have probably been very lucky with M2 it holds a much better edge for me than the ATS/CM series and steels up a treat. I have never had any trouble with rust. I find M2 a delight to sharpen as well. How anyone can argue against my findings is beyond me

Point being my mileage is WAY different to others. Call me lucky, but that is my personal findings and all a I am doing is passing those on in the hope it helps others. While I understand my opinions are not as valued as a knife maker, I notice Joe agrees with me on this. I was somewhat disturbed that M2 did not sell as well as it deserves. The BT2 coat and rust worries are the reason. I agree that BT2 looks like crap the first time you cut cardboard, but as a user knife I cannot rave more about BM's M2.

No I am not looking for a fight and I hope this finds you in good humour!

W.A.

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OwenM · Mar 14, 2001

General,
I have had no problems with corrosion with the 710HS, either-and the finish is completely gone from the thumbstuds forward. I agree about the coating, but wouldn't mind seeing an uncoated M2 blade as an option, however unlikely.
btw, I just got in from work. Leaving there always puts me in good humor!

Joe,
This talk of lock confidence and applied pressure, and the fact that most of us do not have the same knife in a variety of steels, has me thinking about edge thickness, blade grind, and handle comfort as having an effect on edge retention.
Would you use a knife harder if you didn't experience discomfort during hard use?
Does a high grind that allows you to make a cut with less effort (and therefore less pressure) aid edge retention, since you're not having to force the blade through the material being cut?
If a thinner edge cuts better, and with less effort than a thicker edge, does this somewhat offset the added strength of a thicker edge bevel?

So many little things that may have an effect on the results we all get. No wonder so many different people can have so many different opinions on the same thing.
This little discussion seems simple enough, but it's actually changing the way I look at my knives, and has me second guessing myself on things I thought I had pretty strong opinions about.

See what happens when you make me think?

mjoury,
Sorry to get off-topic on your post. Whichever steel you choose, check out Joe's technique for sharpening the 710:
http://www.bladeforums.com/ubb/Forum3/HTML/000560.html
It works. Recurves rule!

[This message has been edited by OwenM (edited 03-14-2001).]

mjoury · Mar 14, 2001

Originally posted by OwenM:

...
mjoury,
Sorry to get off-topic on your post. Whichever steel you choose, check out Joe's technique for sharpening the 710:
http://www.bladeforums.com/ubb/Forum3/HTML/000560.html
It works. Recurves rule!

Owen,

No problem! I am learning all sorts of stuff from this -- very helpful for a newcomer to these forums. Thanks for the link to Joe's writeup.

From all the assorted posts, info, and advice I think that I have taken a slight leaning towards the M2 blade. It is going to be a couple of weeks yet before I get one so I might yet change...

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Marwan

Cliff Stamp · Mar 14, 2001

OwenM:

Does a high grind that allows you to make a cut with less effort (and therefore less pressure) aid edge retention, since you're not having to force the blade through the material being cut?

Yes, or looked at another way, it reduces the amount of work you have to do to achive a set goal. For example, slice through a rope with a 15 degree bevel and with a 25 degree bevel, both using the same amount of force, the amount of edge that needs to be used (in length) is much greater for the 25 degree bevel.

If a thinner edge cuts better, and with less effort than a thicker edge, does this somewhat offset the added strength of a thicker edge bevel?

Exactly. I have been thinning out all my edges gradually and now am down to under 15 degrees on everything including the heavy wood choppers, most everything else is under 10. I have not seen a rapid degrease in edge holding, nor have I heard any such comments from the people I loan my blades out to.

I have been meaning to quantify this in some decent manner but the amount of mundane work it would involve (grinding at least four successive bevels on a blade 25,20,15,10 and doing some work and comparing the edge retention), puts me off. I don't mind the cutting and such, but reprofiling is a pain. As well since all my blades are really thin edged, I would have to go the other way and then grind them back again, a large waste of steel. I'll probably do it on the next blade I get with a thick edge.

It should be noted that in some materials, the geometry of the edge bevel is not completely the deciding factor in the cutting ability. If the primary bevel is also a major factor then thinning out the edge bevel will not have as dramatic an effect on the cutting ability and thus you don't get the offset you described. All you have achieved is to weaken the edge excessivly and the blade now dulls quickly.

You can't ignore this effect in any material however and it determines basically the optimum "thinness" you can achive without losing too much edge retention. It is kind of a critical point, so once you thin the edge past it, the primary grind becomes a major factor in setting the cutting ability, and now you start to lose edge retention.

To again restate one of the more critical points Joe made, becuase M2 is much more durable than ATS-34 (and yes, I include Bos work, I have used 3 examples of it), you can either keep it at the same profile as ATS-34 and use it over a wider range of tasks (rougher work), or thin it out to the desired durabiliry level and get a better cutting knife. Either way the M2 blade will be a better tool - except of course if corrosion is a significant factor.

-Cliff

[This message has been edited by Cliff Stamp (edited 03-14-2001).]