There’s a tremendous amount of discussion about “Spin Grinding” vs. “Relief Grinding”, but the truth is anyone can “spin” grind with similar “sharpening” results. While some propose that the type of finished “spin” grind can be different from various grinding systems in the field, fact is, we all produce the same “sharp” edge with equal results, and the claims of getting a special impact grind or “auto-relief” can be misleading. The photos on the side show what can be expected.
Bottom line? Results show little difference in the spin grind process from one style of grinder to another. All grinders capable of spin grinding will produce similar results with slight deviation from the front cutting edge to the rear of the blade. This results from the reel blade rotating backwards and when it contacts the stone, the rear of the blade hits first and takes the biggest impact. All spin grinders produce this impact grind. As the blade continues its rotation across the stone the stone peels metal toward the front edge, which produces the burr that you feel on the cutting edge when the grind is complete, and the blade is sharp.
In Depth Look