I went to a demo yesterday and the instructor had a diamond hone block about 3" x 5" to touch up his spindle gouge. You could see the impact of a touch up immediately. Only a few swipes was necessary to get the tool freshened up and going at its best again. I wished I had asked him what it was and where he bought it.
Looking for insights and recommendations. (size, grit, sourcing, experience, . . . )