Stepped Drill Bits

Show me the range of stepped drill bits needed for pre-drilling pilot holes in aluminium and steel for threaded studs

TX-BT 4.7/7 Stepped drill bit Stepped drill bit for pre-drilling holes for new-generation X-BT fasteners

Stepped drill bit TS-BT 5.5-74 S Stepped drill bit for predrilling accurate holes for S-BT threaded screw-in studs on aluminium and steel