A Lapping Technique...

...you guys probably already do. But I discovered it for myself (which is a rare thing for me), so I thought I'd pass it along in case it's new to someone else...

I had a DMT xcoarse (still have it, actually, it's my main lapper) that had a few high diamonds in it. It was causing a few very nasty scratches in all the stones I lapped with it. After I knocked the diamonds down to size, I really started criticizing the surface the DMT was leaving in the stones. I wasn't that happy with it, so I started doing what Glen suggested: using the next grit size down in stones to put the final finish on a stone after lapping, i.e., if I just lapped my Shapton 16k, use the Shapton 8k to put the final finish on the 16k. That worked very well, until...

I noticed that if I left a good amount of slurry on my coticule while lapping it, it came out very, very smooth compared to how it looked if I lapped it under constantly running water. The running water left the coticule's surface exposed to the nasty diamonds of the DMT lapping plate on a continual basis. Taking the water away from it allowed the garnet-filled slurry to act as a buffer, and do their *own* lapping/polishing on the coticule's surface. So I started doing this to my snythetic's, too; for the final "polish" after lapping, I'd let the stone's own "slurry" accumulate to polish the stone with it's own slurry for a few minutes after the actual lapping is complete. It works just as well with synthetics as it does with naturals, and you get a finish that is the same grit as the stone. This works best if you really back off on the pressure applied to the two stones, or else you get two problems: huge stiction, and the finish won't be nearly as good.

FWIW. :)

I think it's really cool that you've experimented successfully, and that you're sharing what you've found. I would just add in a word of caution to be careful which DMT's you try this with. The finer DMT's are more likely to have the diamonds stripped off of them when a slurry builds up (and that may depend on what hone you're lapping too). But sounds totally safe with the XC.

Very cool.

Maybe I'm paranoid but I try to avoid slurry build up with diamond plates unless I'm using them as a slurry stone :p. No experience with the DMT XC tho.

btw, I found a short time on a Spyderco UF knocked high spots off my diamond plates very efficiently.