CPM M4 edge thickness

Joined
Dec 21, 2006
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Hey guys, the CPM M4 should be coming in this week, and I plan to make some hunting knives. I ACTUALLY DID a search :thumbup: on Bladeforums, and I think I found the answer I was looking for, but maybe there is something I am overlooking, you more experienced and "wiser" fellas can steer me right.....as opposed to steer me left. My question was, if sending out to Peter's for heat treat, what thickness should I leave the edge on a CPM M4 hunter (and I like really thin edges). It seems that regardless of carbon, stainless, or tool steel, Brad requires an edge of .015" minimum. If I were to take it down that low (let's say .020"), is this sufficient for decarb concern? (I don't know their process....anti scale coatings? cryo treatments? I am pretty sure they do cryo when the steel requires it, I think CPM M4 requires it?). This may be more properly directed to Brad, but I always value your thoughts. If they negate decarb in their process, I would really like to take it to the .015". If not, then maybe a bit thicker edge will be needed. I may be splitting hairs here, so let me know if that is the case. Wait a minute....aren't we supposed to be able to split hairs after stropping?
 
I would say to take it to a nice satin 400 grit finish and leave the edge at .005-.010" . If Brad wants thicker, go .010-.015". I think mine are thinner when I send them in.
M4 is a bear to take down after HT.
 
I have sent Brian both M390 and S35VN. Both times he said to take it to .010.

Tim
 
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