Why does CPM-M4 dominate in national cutting competitions?

tan(angle)/ = half of the thickness of spine / width of blade.. Actually, that will be half the angle, the inclusive angle will be twice that. So (arc tan (half thickness/width))*2 = inclusive angle
 
Mr. Phillips,

I just wanted to say thank you for your contributions to this thread. I have learned a wealth of information from your posts. It is great to have someone on here who has been there done that contributing to the thread. It is great to see you on the boards, I hope to see you on the boards more. Thanks again for sharing your knowledge!
 
dphillips said:
I didn't realize it was that acute. May I ask how you figured that? Thanks in advance.
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Sodak has it. It's trig. Because you are sharpening basically from the edge to the spine, the angle is pretty acute.

I don't know how much of an explanation you want. But the calculation is for a right angle. If you split your blade profile in half, cutting from the tip to the middle of the spine, you get two right triangles, each with a 3/16 inch spine (side opposite) and 2 inches long on the adjacent side.

The tangent = the side opposite (opposite of the edge angle at the tip) divided by the adjacent side (adjacent to the right angle), or 0.1875/2.

Tangent = 0.09375, which converts to an arc tangent (angle) of 5.3558 degrees, which you double to get the inclusive angle of 10.7 degrees.
 
trailside22 said:
Mr. Phillips,

I just wanted to say thank you for your contributions to this thread. I have learned a wealth of information from your posts. It is great to have someone on here who has been there done that contributing to the thread. It is great to see you on the boards, I hope to see you on the boards more. Thanks again for sharing your knowledge!
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It was my pleasure, I rather enjoyed it. If someone starts a competition thread let me know, I'll be there.
 
dphillips said:
thanks
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No. Thank you, sir. I've REALLY enjoyed both your videos and your explanations. It's a pleasure to see someone at your level talk about what you do!

Twindog said:
Sodak has it. It's trig. Because you are sharpening basically from the edge to the spine, the angle is pretty acute.

I don't know how much of an explanation you want. But the calculation is for a right angle. If you split your blade profile in half, cutting from the tip to the middle of the spine, you get two right triangles, each with a 3/16 inch spine (side opposite) and 2 inches long on the adjacent side.

The tangent = the side opposite (opposite of the edge angle at the tip) divided by the adjacent side (adjacent to the right angle), or 0.1875/2.

Tangent = 0.09375, which converts to an arc tangent (angle) of 5.3558 degrees, which you double to get the inclusive angle of 10.7 degrees.
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Thanks Twindog! I should have added more verbage, but you nailed it! :D
 
Interesting thread. It took a detour toward the middle but Mr. Phillips' contributions turned it around. I REALLY enjoyed that video and your information about the competitions. Thanks for your interesting and informative posts.
 
Since the topic of this thread has been pretty thoroughly discussed but has obviously generated a lot of interest in cutting competitions, I have started another thread in this forum for ongoing general discussion about cutting competitions. It is titled "Cutting Competitions".
 
O.k. I realize that this post is really old so few will see this but any way,

I don't want to hear about hype. I started making knives, very young, and in high school I started looking for the "best steel" I was enthralled by Wootz, and then I found HSS, and then CPM HSS, and after carefully considering almost every data sheet Crucible had I concluded that M4 was the best. I had absolutely no contact with other knife makers or enthusiast. Crucible does not market toward knife makers, they do not even sell retail, what your talking about is INFI. Busse (and others) claim it is the best but he has released no real data, just showy comparisons. If you guys want perfect comparisons Crucibles data sheets are amazingly complete.

In my opinion CPM M4 is the Best
 
Hey Nebulae, glad you found this thread. What kind of blades do you use CPM-M4 for? Just curious. I use it for my personal blades, from a 2.5" caper to my comp knives. Just like talking to other people who have used it.
 
I have a Tom Krein Ultimate Caper in M4. It has a full height hollow grind and .007" edge at 7 degrees per side. It gets sharper than any other knife I own, and it is just a great cutter for utility or paring work. My other M4 knife is a Spyderco Mule, and it gets extremely sharp and holds that edge real nice, just like my Ultimate Caper. They may not have the edge retention of ZDP 189 or S90V, but they get sharper and hold that extreme level of sharpness a long time. I need to do some tougher cutting with my Mule and it's .019" edge at 10 per side to see how it does at cutting wire and light chopping and batoning. Both are around 62 RC and I'm imagining will have plenty of toughness for some light batoning and chopping, and with the great sharpness that Mule should be a wonderful whittler. I'm eagerly awaiting my Spyderco Gayle Bradley folder in M4, as it should be a great pocket knife. California has crappy fixed blade laws so the Bradley will allow me to carry some real nice M4 around in my pocket to enjoy it every day.

Mike
 
gunmike1 said:
I have a Tom Krein Ultimate Caper in M4. It has a full height hollow grind and .007" edge at 7 degrees per side. It gets sharper than any other knife I own, and it is just a great cutter for utility or paring work. My other M4 knife is a Spyderco Mule, and it gets extremely sharp and holds that edge real nice, just like my Ultimate Caper. They may not have the edge retention of ZDP 189 or S90V, but they get sharper and hold that extreme level of sharpness a long time. I need to do some tougher cutting with my Mule and it's .019" edge at 10 per side to see how it does at cutting wire and light chopping and batoning. Both are around 62 RC and I'm imagining will have plenty of toughness for some light batoning and chopping, and with the great sharpness that Mule should be a wonderful whittler. I'm eagerly awaiting my Spyderco Gayle Bradley folder in M4, as it should be a great pocket knife. California has crappy fixed blade laws so the Bradley will allow me to carry some real nice M4 around in my pocket to enjoy it every day.

Mike
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Do you have any pictures of the Spyderco Gayle Bradley folder? I've been eagerly awaiting this knife, I would even buy it w/o ever having seen pictures of it!

I have my CPM-M4 Mule at 8 degrees per side and have chopped wood with it, the edge holds up just fine. It's a really strong steel, basically M2 with better edge retention. It takes as fine an edge as 52100, though 52100's edge wears more smoothly.

I would love a straight razor made out of CPM-M4. According to Crucible the pitting resistance is really good, unlike CPM 3V.
 
I don't use M4 for many b/c of the cost, but I am planing to make a superb 8" fighter out of it soon
 
Nebulae said:
what your talking about is INFI. Busse (and others) claim it is the best but he has released no real data, just showy comparisons. If you guys want perfect comparisons Crucibles data sheets are amazingly complete.

In my opinion CPM M4 is the Best
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Have you ever used INFI?
 
what do you mean, have I made a knife from INFI, no,
Busse does not sell INFI in billets, does he? I would love to get some.
I have not bought a Busse knife either they are kinda spensive, and I am dubious about the whole INFI thing.

Busse uses some nitrogen that is supposed to help with corrosion, but usually nitrogen, and other gases introduced into steel have negative consequences. as far as INFI goes I think that if he could somehow teem up with crucible, and make his steel using powdered metallurgy, (perhaps with some minor adjustments from crucible), he could end up with the best blade steel ever.
But as it goes I am going to stick with M4, because I know it, there is no mystery, and I want to make my own fixed blades.
 
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No, I know you probably haven't made a knife from INFI, unless it was some sort of modification of an extant knife. Just curious about the basis of your conclusions. That's all.

Folks who do use the steel on a regular basis hold it in esteem, and these are knife knuts who buy all brands and love to try different steels. I'm one of them. I have choppers in a pretty wide range of steels, though I do admit M4 isn't one of them. My favorite INFI choppers are excellent performers and hold an edge like nobody's business. I don't have data charts or fancy terminology. I've never participated in a competition. I haven't broken one apart with a 3-pound sledge. :p But I can say they perform extremely well in real-world usage.

Just trying to keep things in perspective and temper the "hype" hype.
 
don't get me wrong I think INFI is a great steel, and I intend to buy at least one of his knives when I can. But for me M4 makes more sense. It would be interesting though to learn what exactly goes into INFI, and to actually compare the two knives, beyond the steel data charts
 
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