The Grob Rolling process increases the strength by rearranging the grain structure of the material over the entire tooth profile. The greatest amount of strength is gained near the bottom, or root area of the form where strength is most crucial. Note the tighter grain structure of a cold rolled tooth form (left) as compared to that of a cut gear (right). The result of the cold forming process produces a very high surface finish. Roughness average, (Ra) Readings of 4 micro inches have been produced.