B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
B23F—MAKING GEARS OR TOOTHED RACKS
B23F5/00—Making straight gear teeth involving moving a tool relatively to a workpiece with a rolling-off or an enveloping motion with respect to the gear teeth to be made
B23F5/20—Making straight gear teeth involving moving a tool relatively to a workpiece with a rolling-off or an enveloping motion with respect to the gear teeth to be made by milling
B23F5/22—Making straight gear teeth involving moving a tool relatively to a workpiece with a rolling-off or an enveloping motion with respect to the gear teeth to be made by milling the tool being a hob for making spur gears