Reply by JayT

Diamond plates do have a break-in period where they cut more aggressively than the grit until some of the diamonds fracture and settle in. I’ve been using EZE-Lap plates for several years now and am very happy with them. Took sharpening half a dozen plane irons or so before they broke in and then have performed admirably since.

When doing plane restorations, however, I use sandpaper rolls on granite. More for the length than to save the sharpening plates. I usually stop at 220 for users. Any more than that is just extra effort for no performance gain. If you want to use higher grits to get a mirror finish because that’s the look you want, have at it, just don’t expect the plane to work any better.

-- https://www.jtplaneworks.com - In theory, there is no difference between theory and practice. In practice, there is.