- Northern Industrial Tools Wet Sharpening System - 8in. Wheels Rotates at only 120 RPM Wet bath sharpens without overheating 8in. leather honing wheel polishes blades to a mirror finish with included honing compound Knife jig handles blades from 1/2in. to 4in. long Jig for straight edges, plane irons, ripping chisels and spoke shave blades