Socket cap screw counterbore

Specifications:
Screw size:3mm-20mm; Pilot diameter:3.4mm-21mm;
Cutting diameter: 6mm-33mm.

Features:
3 flute,straight shank or taper shank,solid pilot,high speed steel.

Counterbore sets:
7 Piece Set
contains 1 piece each:
No.6, No.8, No.10,
1/4, 5/16, 3/8, 1/2.