I'd be worried about grit contamination with the diamond pastes, though...
I'd be worried about grit contamination with the diamond pastes, though...
It's a problem with basically any abrasive medium. It's not like waterstones retain their abrasive particles particularly well, and even lapping films, sandpaper, oil stones, and ceramics can kick loose the occasional bit of abrasive.
As Bruce says, you just have to observe sound cleaning processes when switching grits. I'm not quite as ballsy as he is, though - I dedicate a plate to each grit.
I've also moved to the paste on mild steel - nothing I've tried is faster, flatter, etc. -The Gramercy paste kit with the LV plates specifically. A quick wipe with an alcohol-wet rag before switching to each plate is all I find necessary to keep from cross-contaminating. Once in a while, I clean the plates completely and reapply fresh paste (but I haven't found that necessary too often).
@Patrick - you mentioned having to flatten the plates. I think I'd rather buy new plates. How much use did your plates see before you had to flatten?
"The reward of a thing well done is having done it." - Ralph Waldo Emerson
As with everything else I've perhaps overdone it with paste-based sharpening.
I use Sandvik-Hyperion (from McMaster-Carr) and Norton (from TFWW/Gramercy) water-based pastes, and PSI oil-based pastes. I have a mix of Veritas plates and ones that I've cut out of precision-ground mild steel stock from McMaster and Online Metals, as well as a couple cast iron plates. I mostly use acetone for tool and (when needed) plate cleaning. I also use the "Hyprez" extenders/lubricants that McMaster sells to thin/lubricate the diamond paste.
I use grits as coarse as 60 um (200-250 grit equivalent) and the plates for those coarser grits can go noticeably out of flat within a matter of weeks of heavy use if I'm not careful enough about distributing the sharpening uniformly. Of course they don't need to be as flat as the plates for finer grits, but even so I flatten them with SiC grit on a granite surface plate, using a laminating sheet both to protect the granite and to speed things up (softer lapping surface -> faster lapping). I find that it's worth my time to flatten as it's reasonably quick provided I don't let the plate go too far out of whack.
Yep...yet another "sharpening thread".........
It's truly our favorite pastime.
Bumbling forward into the unknown.
Indeed. If you take a look back, this thread went to the sharpening dogs in post #10, when *somebody* made the teeny tiny leap from overly failure-prone edges to overly harsh abrasive particles.
Hah, we just love debating about sharpening. I feel like I've learned a lot from all of you thanks to this habit, though.