Thread: Convex edge

From my thread about using hanging pasted strops...

So, I did a very quick test last night on a warped Wapi. I put three sheets of paper (wetted out) under my diamond lapping film, and honed it up: 9um, 6um, 3um, 1um, 0.5um, 0.1um.

There was definitely some convexing going on. Using the polarizer filter on the scope (it doesn't come out in the image capture, however..) it was apparent that the bevel had some curvature to it.

The result?

Well, the bevel sure is smooth & shiny!

And subjectively, the actual edge seems to have less microchipping and edge distortion than the 0.1um edge I put on another razor using the film flat on the precision plate without the paper backing.

Not a real good comparisson, because different razor steel may react differently, etc...

Anyhow, I may reduce it to just one sheet behind the lapping film, and see how that goes...

Seraphim,

I really appreciate your approach to honing and the experimentation, as well as the posted results and pics. It's really interesting to see that others are willing to go out on a limb, too, and break out of the standard "box" or.... pyramid for some...

We've had the discussion of convex vs flat bevels for a long time over on Knifeforums, and I've always found a combination to be good. Hone a dead flat bevel as fine as you can, and then finish a knife off with leather and chromium oxide or the like. It imparts a slight convex bevel just at the very edge, and it is a good thing. i was thinking that this would be good for your experiment, too. If you were to hone on the diamond sheets while they were flat on your granite reference plate through 1um, then put the wetted paper under the diamond .5um and .1 um sheets for the final touch. that way only the tip of your bevel would be convex, and when you need to return to the hones you won't have so much convex material to remove before you reach the edge. The convex section would have an extremely small area, and upon subsequent sharpenings I think it would be very easy to hone a new flat bevel all the way to the extreme edge with minimal steel removal, and the edge would be better supported and last longer, and more resistant to deformation at the edge. Just a few thoughts.

I think that i sbasically what my "standard" finishing on hanging strops does--i.e.- adding just a touch of convex to the very edge (actually I can see that is what it does under the scope, just can't capture that image yet).