Quote Originally Posted by DaveW View Post
ER...the spydercos are maybe harder than biggs and owyhee jasper. And not flat when they're new. I've lapped an 8x3 UF with an atoma 400, but I think it took a lot of stuffing out of the atoma (which is my preference over a DMT, but it does wear to a point of slower cutting like the DMTs do, it just seems to be a little more indestructible since the stones are arranged in blobs on it instead of one by one)
Yes the UFs certainly take the bite out of the Atomas also. I had a 4oo with a tiny high spot & just used the corner of a UF to knock it down. Problem solved in seconds.

The best way to lap UF's that I found was with a slurry of SiC powders starting@ 80 grit or lower on float glass. Very fast & saves the diamond plates. Diamond powder slurries would work too but more exe.