Severance Chatter Free® Stop Countersink Cutter 82 Degree 5/8" Diameter 1/4 Pilot Hole, Field Tool Supply Co, Mfr#: 6815524$76.99+
# 5 Complete Countersink W/Taper Drill & Quick-Change 1/4†Hex Shank Adapter, Big Horn, Mfr#: 18901$35.15+