Screwed up the edge on my new back pocket.

Joined
Mar 17, 2011
Messages
185
Got a new back pocket the other day. The factory edge was okay. I sharpened it until it would cut a hanging hair with a little swipe, but it jut wasn't hair whittling. Well that bugged me so this afternoon I decided to stop it. I very gently stopped it on chromium oxide about 30 strokes per side and I mean light strokes. Pulled out some yellow pages that it was push cutting fine before expecting light saber cuts. :( wrong the edge was totally wrecked. I don't get it, I was careful to keep the angle and used light strokes. I had to go back to the stones to get it back. I looked at it with a 30X loupe and it didn't look rounded and there was no wire edge. Oh the mystery of steel and me! Discuss please
 
Joined
Apr 12, 2009
Messages
12,091
Assuming this is a Case Back Pocket? Is it stainless or CV?

The cutting will always 'tell the tale' about the edge, regardless of whether it looks OK (by eye or magnified). There's definitely something going on with the edge. I'm betting there was a fine burr which was cutting the hair, but stropping removed it. The hard edge behind the burr is either too wide or otherwise blunt/rounded. A light sharpening of the factory edge might not quite get it super-sharp, if the edge angle is a bit too wide. Shaving/hair-whittling gets easier when the edge angle is down to 30° inclusive or less. Trying to do it at 40° or more will be challenging. I've re-bevelled almost all of my Case knives to ~30° or less (usually), and this makes a big difference in cutting performance. Almost all of mine are the stainless versions (Tru-Sharp, a.k.a. 420HC). This steel can make some very fine slicers, especially in combination with the thin hollow grinds on most of Case's knives.

The shaving or hair-whittling tests won't distinguish between a burr (which can easily shave) or a truly durable edge, which will hold up much better to stropping/paper-cutting/etc.


David
 
Joined
Mar 17, 2011
Messages
185
Yes it is a Case back pocket in CV. I am trying to keep the factory bevel at this time.
 
Joined
Oct 4, 2010
Messages
1,315
Assuming this is a Case Back Pocket? Is it stainless or CV?

The cutting will always 'tell the tale' about the edge, regardless of whether it looks OK (by eye or magnified). There's definitely something going on with the edge. I'm betting there was a fine burr which was cutting the hair, but stropping removed it. The hard edge behind the burr is either too wide or otherwise blunt/rounded. A light sharpening of the factory edge might not quite get it super-sharp, if the edge angle is a bit too wide. Shaving/hair-whittling gets easier when the edge angle is down to 30° inclusive or less. Trying to do it at 40° or more will be challenging. I've re-bevelled almost all of my Case knives to ~30° or less (usually), and this makes a big difference in cutting performance. Almost all of mine are the stainless versions (Tru-Sharp, a.k.a. 420HC). This steel can make some very fine slicers, especially in combination with the thin hollow grinds on most of Case's knives.

The shaving or hair-whittling tests won't distinguish between a burr (which can easily shave) or a truly durable edge, which will hold up much better to stropping/paper-cutting/etc.


David

I agree with David - the factory edge probably had a small burr which got removed by the stropping. With a little sharpening, you can put a much better edge on that Case that came with it from the factory!

TedP
 
Joined
Mar 17, 2011
Messages
185
No no I sharpened it before this happened. There was no visible burr at 30x after I sharpened it before I stropped it. Sorry for the confusion.
 
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