Drill America DEWMSKSET-82-5 5-Piece HSS Machine Countersink Set (1/2"-1"-82 Degree) - High Speed Steel Countersink Bits for Metal, Wood & Plastic Drilling - Perfect for Metalworking, Woodworking & DIY Projects

Working on an old 1948 truck grille and using a 1/8" countersunk pop rivet on 14 Ga. mild steel. Had to countersink about 70 1/8" drilled holes. Keeping the drill speed down so as not to heat up the tip which kills any drill, I was able to easily countersink the holes and install the pop rivets with the results I had hoped for. I'll finish these up with a little fiberglass bondo and sand smooth, and its ready for primer.