Description
Class B21H : MAKING PARTICULAR METAL OBJECTS BY ROLLING, e.g. SCREWS, WHEELS, RINGS, BARRELS, BALLS
Subclass 1/08: Making articles shaped as bodies of revolution (rolling tubes B21B 17/00-B21B 25/00) rings of restricted axial length (extending closed shapes of metal bands by simultaneous rolling at two or more zones B21B 5/00) railway wheel rims