Many woodworking instructors such as Toshio Odate and David Charlesworth advocate a slight convex radius on the cutting edge of plane irons. This curved or cambered edge prevents ridgelines when smoothing, promotes rapid stock removal during flattening and produces gapless seams when joining.

These diamond-covered, cast iron plates are manufactured slightly concave (.0025" hollow) across their width to rapidly shape this type of cutting edge. They measure 3-1/4" wide x 7-1/8" long x 1/4" thick and will accommodate almost any plane iron.

The 325x (45mic) plate is a coarse abrasive. It reshapes blade geometry as well as removes minor edge defects. 220x (60mic), 600x (25mic) and 1200x (9mic) plates are also available.