7Pcs/set Counterbore Drill Bit Sets HSS Counterbore End Milling Cutter M3.2-M12.4 Countersink Drill Bits Pilot Slotting Milling Cutter End Mill Cutting Tool Set for Copper Aluminum Cast Iron - Amazon.com
CRAFTSMAN Counter Bore or Countersink For Brace 23052607
Counterbore - Wikipedia
Voile Counter-Bore Drill Bit for Split Hooks: Voile
Amana AA55102 Countersink and Counter Bore Drill Bit - RTA Furniture Drill/Countersink - 3.5 mm Diameter