CPC Subgroup
B23C 3/32 Milling helical grooves, e.g. in making twist-drills
Full Title
Milling particular work; Special milling operations; Machines therefor (milling gear-teeth B23F, ) > Grooving workpieces (tread-cutting by milling B23G1/32) > Milling helical grooves, e.g. in making twist-drills