Abstract: Hollow-ground surfaces are simultaneously formed along opposite sides of a knife blade blank by passing the knife blade blank between a pair of grinding wheels. The grinding wheels carry grinding belts about idler pulleys. The idler pulleys are adjustable toward and away from the respective grinding wheels to adjust belt tension and to accommodate different sizes of grinding belts. The angularity of the idler pulleys relative to the grinding wheels is likewise adjustable such that planes passing through the idler wheels and grinding wheels are angularly adjustable relative to one another enabling the grinding belts to run true about the grinding wheels.