School me in cpm m4

[james terrio]

However for every minute of competition, I log perhaps 50-100 hours of continuous practice (I don't compete very often). My point is, some make the mistake of thinking our edges only need to (and therefore only do) last a minute or two. I generally strop my blades for a minute or two after each practice session (generally lasting a couple hours) and only need to (truly) sharpen it once ever 4-8 sessions. At that point it will still rough shave arm or leg hair, but there will be small nicks in the blade that impact slicing performance.

Thanks for the clarifications

 

[Omega Leather Works]

yes, it's a knife edge, sometimes they take damage. maybe you hit a small piece of staple you didn't see. maybe the factory edge had a wire edge, who knows. If it's not in a 100% controlled environment, and it's a one time thing I wouldn't worry about it.

Yeah, I guess I'm not too worried about it. There's no way I hit a staple though. I've actually only cut a handful of things and every one with care. I guess it becomes easy to over estimate a steel when you read things posted like what's written in this thread.

 

[unit]

Yeah, I guess I'm not too worried about it. There's no way I hit a staple though. I've actually only cut a handful of things and every one with care. I guess it becomes easy to over estimate a steel when you read things posted like what's written in this thread.

Steel is one thing. Heat treat, blade geometry, edge finishing, and use are serious variables.

Fo what it's worth, I run my comp knives at an edge angle of 20-25 degrees inclusive and work them quite hard. I once was chopping a board that had a stone embedded in it and the contact resulted in a chip in the blade, but the edge has never rolled in countless hours of use.

I have a custom EDC knife in M4 that I have contacted steel with...that caused a nice roll in the edge.

M4 is a nice blade steel, but it's not without limits. I would suggest something that is actually quite well known amongst steel "testers". Cardboard is a TERRIBLE test material for edges because of the variables within. Food grade (for pizza boxes as an example) is one thing, industrial/recycled grade is quite another and it often contains all sorts of contaminants that will roll edges readily.

 

[Twindog]

Steel is one thing. Heat treat, blade geometry, edge finishing, and use are serious variables.

Fo what it's worth, I run my comp knives at an edge angle of 20-25 degrees inclusive and work them quite hard.

What blade thickness do you like for your competition blade? Is there a blade thickness that is most popular for competition?

 

[Omega Leather Works]

I completely agree about cardboard. After chipping my knife in s30v twice I only use cheap knives to cut the stuff. My Opinel (in Carbon) for instance, works very well. The edge will roll as it is pretty acute, but it's never chipped and it's very easy to set straight. Much more fun than a box cutter.

I dunno, maybe it was the clamshell that did it on the 810. Couldn't have been the lasagna box, which was like thick white paper. You know the stuff.

I think I'm going to try to replicate the roll using the same materials that I've already cut. I guess this is more about this particular knife in m4 than m4 in general, but I don't care, it IS my thread after all. I never care when they go ot.

 

[unit]

What blade thickness do you like for your competition blade? Is there a blade thickness that is most popular for competition?

The spine thickness is really a function of the strength/power/speed of the cutter. If I could, I would have the thinnest blade possible, but I need enough weight to carry the blade (inertia) through the heavy cuts but not so much that I loose control on the finesse cuts (I'm not the biggest guy that does this sort of thing)

That said, my cutters are a shade under 0.33 inches at the spine. The thinnest I have seen was a bit under 0.25 and the thickest I have seen was about 0.4

The regulations dictate certain things, so blade thickness is a result of desired weight.

If a blade ever fails it it generally during practice (never heard of a breakage at competition...and it is heavily frowned upon in comp). When a 'break' occurs it is in the form of a crack or chip out of the edge where the steel is ground thin...and results in immediate disqualification if it happens in comp.