I am currently interested in making some lapping plates due to watching some Tom Lipton videos.
How would you keep the granite lap true?
The 3 lapping plate methods of keeping them true Seema easy enough, but how would you maintain the surface?
As far as cutting the groves, cutting with a wet saw would be necessary. Trying to cut dry, either with a grinder or with a radial arm saw, would cause the blade to chip the edges as it cuts. Cutting try produces a rough cut.
A high quality belt driven wet saw produces a better cut, but good wet saws are expensive and a lot of saws, the blades don't raise that high. My target tilematic could probably do it. But it's a lot of weight on the table.
Interesting idea.... The b grade plates are only $50 around here.