Tooth grinding is the finishing of the tooth with a grinding operation. Grinding work is typically more accurate than a hobbing operation. In addition, “harder” products cannot be milled and have to be grinded. The tooth grinding or teeth grinding therefore is often done as finishing after the hardening process. As a result of the hardening process the teeth become much harder (= more wear resistant) but there also arise undesirable distortions. Therefore is often chosen to grind the teeth after the hardening which results in high quality gears.