For abrasive materials. Tools will drill countersink and finally counterbore a parallel hole. Designed to receive plug produced by maker Ref. 24 group. The drill diameter sizes are for a clearance hole only.

Specification:
D=3/8 inch
D=9.5 mm
D2=4.8 mm
C=20 mm
OL=62 mm
Shank Diameter=1/4 inch
Wood screw size=No 8