B0003Push-in drill bushes, DIN 173, part 1, Form KItem description/product images Description Material: Special steel Version: Hardened to 780 ±40 HV 10 and ground. Note: All bushes have the bore size marked on the upper face, e.g. 15 F7. Form K are quick-change bushes. Dowels or coiled spring pins together with DIN 173-1 flathead screws can be used in place of the stop pin. The bayonet mount is secured with DIN 173-1 drill bush clamps together with DIN 912 socket head screws. E2 = Hole spacing when using dowels or coiled spring pins. Diameter D1 over 15 mm increase in size by 0.5 mm.