Why does CPM-M4 dominate in national cutting competitions?

Broos said:
After seeing that, I could see some folks wanting one. I don't think it is an unreasonable question to ask that if some of the higher carbide steels fail (apparently via fatigue from flexing), is there concern by the competitors that a steel with slightly lower carbide fraction would experience the same fatigue, just at a slower rate. For a user and a keeper, I like cutting performance, but not at the cost of any risk of a reduced life due to fatigue from flexing. So maybe getting one a little thicker than the "competition grind" is appropriate for one you want to use for a long time, no?
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Sounds reasonable to me!:)
 
I appreciate the answers & the links, Donavon. Good luck in your upcoming competitions!
 
Can someone explain the idea of metal fatiguing vs. work hardening?
It seems like if the edge is moving during a cut and weakening over time, the next sharpening would remove the weak part...or is the flexing of the entire blade the problem?
 
dphillips said:
http://www.youtube.com/watch?v=GDoGtY4pyYw Donavon
http://www.youtube.com/watch?v=QDiQaG_usi0 Scott
http://www.youtube.com/watch?v=-oI-z8i41Do Ted 2x4
http://www.youtube.com/watch?v=JUncTSAEW3w Gayle bottle and rope





This video was done for a website called Bell Bucks and Beards ( http://www.BellBucksnBeards.com ) based out of Indiana. The website is centered around a couple of guys that are serious about keeping there kids outside, in the woods or on the water. I think it is a great site and was happy to do the interview. Thought I would share. http://www.youtube.com/watch?v=wzAo2yZitoU

http://www.youtube.com/watch?v=pyKr2elK3eQ blade show ’09 (all competitors)

http://www.youtube.com/watch?v=1aW1lAmznZ8 Ted all 3 records

M4 knife unsharpened (a little background here. This was my first M4 competition knife and first tapered tang. I was asked to test this knife thoroughly before using it in a competition. So this video was shot as proof that I had tested it well. The knife is not just dull, it is unsharpened which means it has never had the primary bevel put on it, also the handles are not glued on which I payed for later. {bad blisters} The knife was tested with a .016” edge. Enjoy)
http://s637.photobucket.com/albums/...s/?action=view&current=M4knifeunsharpened.flv

Ozark cut May ‘08
http://s637.photobucket.com/albums/uu91/bigdknives/videos/?action=view&current=MyCutOzark08.flv

North Texas cut April ‘08
http://s637.photobucket.com/albums/uu91/bigdknives/videos/?action=view&current=MycutNorthTex08.flv
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Thanks for the links.
 
Great links and information Donovan:thumbup:

I bet a lot of good information could come out on how the edges are retained and created. Stropping has always been a favourite way for me to keep a profile on an edge rather than allow it to be lost....and steels which work well at high Rc settings excel at giving this ability. However...how the edge is taken down to 16 thou is certainly of interest to me...I assume that this is done by grinding and it helps no doubt if you have a "knife makers" professional level of machinery...is the blade taken down this thin before hardening? Or is it taken down say to 22 thou and hardened and the last thininng of the edge done afterwards? Also on convexing the bevel on the edge...is that done using a leather grinder belt or by hand on a strop?

Finally....what depth of spine is preferred if the edge is being taken down to 16 thou? Is this done on a straight tapered flat grind or is the side of the blade geometry convexed?

Thanks for all the time taken to answer peoples queries....:thumbup:
 
Well there is a question here that no one has asked, at that is: How thin an angle is the cutting competition blades sharpened to? 20-40- 15-30- 10-20 etc?
 
samhain73 said:
Well there is a question here that no one has asked, at that is: How thin an angle is the cutting competition blades sharpened to? 20-40- 15-30- 10-20 etc?
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I'd be very surprised to hear that there was a common angle to the cutting edges.

I hope some folks answer this question ... :)
 
I'm just curious, as many steels that excel in edge hold/wear resistance, do not take a very thin edge well, even a very thin convex. Perhaps that is why M4 is used for this application, it can handle that thin of an edge.
 
samhain73 said:
Well there is a question here that no one has asked, at that is: How thin an angle is the cutting competition blades sharpened to? 20-40- 15-30- 10-20 etc?
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from Donavon:

dphillips said:
As far as the angle of the edge it is hard to measure that. I will say that while sharpening on the belt I sometimes accidentally hit the spine on the belt, that is about the only indication I can give of edge angle.
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Not trying to hijack this thread, but how would properly heat treated 1095 or 5160 hold up in these competitions?
 
Not being a knifemaker I wonder what steel is winning cutting competitions in Europe.
I have always been oriented to these American fora but lately I also visited some European knife related fora.
It strikes me they use a lot of steels I never heard from before.
It's harder to follow these fora because of the different languages.
I'm wondering if CPM M4 would also be dominant or if some other steel show better results.
The knife industry in Europe is small in regards tot the American knife industry, but the steel manufacturers are producing very interesting steels that some custom knifemakers seem to discover.
 
Ok, if they are hitting the spine during sharpening, that means a crazy low angle, like flat to the stone zero edge. Which would mean INFI is out, and all stainless, except maybe 12c27 or 420. I don't know if 5160 or 1075 etc. would hold an edge long enough for these tests. M4 really seems to be the best for this application. Wouldn't want to put any lateral forces on it though.
 
AF said:
Can someone explain the idea of metal fatiguing vs. work hardening?
It seems like if the edge is moving during a cut and weakening over time, the next sharpening would remove the weak part...or is the flexing of the entire blade the problem?
Click to expand...

The edge flexing is the problem in the circumstance I am referring to. I am saying edge, the part of the blade I am referring to is the bottom half of the blade. Our blades are 2" wide, if you start at the spine and go down say 1", from there down is where the metal fatiguing happens. The blades I have seen that have broken due to metal fatigue have broken above the actual cutting edge. This is hard to explain but I'm trying. The metal chips out anywhere from 1/8" to 1" above the cutting edge. It can be from a small chip to a crack that runs 1.5" or 2" down the blade. Hope this made some sense.

timsclips said:
Not trying to hijack this thread, but how would properly heat treated 1095 or 5160 hold up in these competitions?
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Someone has already reffered you to post #172, but I would to add some to this. I have not personnally used 1095. 5160 holds up fine as far as toughness. The problem is edge retention. After a comp it will have a serviceable edge, but not still shaving hair or slicing newspaper cleanly. The problem with this is that you have to remove metal to restore the edge for the next comp. After several comps your edge is much thicker than it was when you first made the knife. As far as 1095 I have a knifemaking buddy that has recently started competing that has used 1095. I was using my M4 caper to cut up blue jeans for homemade micarta, he stated after I had sliced up several pairs of jeans that one of his knives would have already been to dull to cut anymore. That is about the only thing I can compare 1095 with. Hope this helps.
 
samhain73 said:
Ok, if they are hitting the spine during sharpening, that means a crazy low angle, like flat to the stone zero edge. Which would mean INFI is out, and all stainless, except maybe 12c27 or 420. I don't know if 5160 or 1075 etc. would hold an edge long enough for these tests. M4 really seems to be the best for this application. Wouldn't want to put any lateral forces on it though.
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Keep in mind, I am referring to a 3/8" thick spine. It is a low angle I just wanted to clarify that.
 
PeterPHWS said:
Great links and information Donovan:thumbup:

I bet a lot of good information could come out on how the edges are retained and created. Stropping has always been a favourite way for me to keep a profile on an edge rather than allow it to be lost....and steels which work well at high Rc settings excel at giving this ability. However...how the edge is taken down to 16 thou is certainly of interest to me...I mark my edge prior to grinding so I am left with a .018" edge or round about there. I flat grind down to these lines and then start measuring with caliper until I get down to the .016" area.I assume that this is done by grinding and it helps no doubt if you have a "knife makers" professional level of machinery..I grind on a 2X72 KMG. .is the blade taken down this thin before hardening? Yes, and the blade is wrapped in Stainless foil to be heat treated. Grinding on M4 after heat treat is a real pain. Actually, my blades are finished when I heat treat. All I want to have to do after heat treat is removed the oxidation layer and sharpen it.Or is it taken down say to 22 thou and hardened and the last thininng of the edge done afterwards? Also on convexing the bevel on the edge...is that done using a leather grinder belt or by hand on a strop? I also put the convex edge on with the grinder using the slack belt technique. I start with a 60 micron, then 30 micron, then ceramic rod and final step is leather strop loaded with green chrome rouge. Removing the burr from M4 is also a pain. Actually, working M4 in general is a pain, but the outcome is worth it in my opinion.

Finally....what depth of spine is preferred if the edge is being taken down to 16 thou? Is this done on a straight tapered flat grind or is the side of the blade geometry convexed? Straight flat grind then convex edge. Not sure what you mean by depth of spine. If you are referring to thickness I use 3/8" stock.

Thanks for all the time taken to answer peoples queries....:thumbup:
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No problem I am enjoying it.
 
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