Which diamond plate for lapping?

[Matt Krusen]

Hey guys, quick question. I'd like to buy one of the DMT DuoSharp diamond plates. I'll be using it primarily to lap/flatten my Shapton stones. What grit combination have any of you used or what do you suggest? Fine/Extra Fine or Coarse/Fine? Thanks!

[Alan Lightstone]

I was just at a Rob Cosman course this week. I have the DMT Diamond Lapping plate, but he said it was too coarse, and will prematurely wear out my Shapton stones. That being said, I do like how quickly it works.

He recommended the Trend Double Sided Bench Stone 300/1000 grit. He was also not fond of the DMT DuoSharps (of which I have two), as he felt they weren't as flat as the Shapton Stones.

YMMV, and this was his opinion, not mine.

[Jim Matthews]

I once owned these and flattened them with a carbide slurry.

You can get appropriate grit from autosupply houses, if you want to go cheap.
The Shapton or Lee Valley product is known to be of good quality, and convenient.

It can be done on a piece of plate glass or dense plastic.

FWIW - I didn't bother much with that method.
I used the next coarser grit to flatten stones together.

Full disclosure - I started using the diamond plate with oil instead of flattening stones.
It's faster, and less to clean up.

It seemed to work, well enough.