Facom 90 Degree Cone Bit for Countersinking -16.5mm Cone width (229.TT3) - drill a pilot hole and follow with the appropriate sized countersink bit. If you use a lot of #12 & #14 screws (or head sizes up to 5/8" in diameter), the 16.5mm countersink is the one to use. These Facom bits have 3 HSS cutting edges for clean countersunk holes. HSS (High speed steel) bits are more resistant to heat than carbon bits.

For use with wood or metal. See photos (click to enlarge) for sizes and dimensions of the 4 different bits. Also available as a 4pc set with lubricant and case....see 229.TTJ4 .