Bought these for a 1980's Omega planer which is almost identical to the Grizzly 1021. Knives fit perfect and are sharp - but - after a few boards I noticed several small ridges.
The first few boards that went through were already planed (just resizing), and the few pieces of rough walnut I pushed through were kiln-dried, brushed, metal inspected and bought from a reputable mill/dealer. I was somewhat puzzled by the ridges but suspected burrs. Inspected the knives and (as suspected) I found no nicks so I decided to remove each knife, and using a ScrotchBrite pad and 600 grit diamond stone, I deburred each knife. There was a noticeable effect, most obvious on the flat (back) of the knife. These are nice knives at a very reasonable price, my only caution is to give each knife a final hone/debur before installing.