Used to produce a close tolerance surface finish by enlarging pre-drilled holes to a finished size. Manufactured from HSS with a 45 bevelled head. Manufactured to BS 328-4.

TOLERANCES (to H7):
Diameter: ~ up to 3.00. Tolerance: +0.008, -0.007.
Diameter: Over 3.00 ~ up to 6.00. Tolerance: +0.010, -0.005.
Diameter: Over 6.00 ~ up to 10.00. Tolerance: +0.012, -0.006.
Diameter: Over 10.00 ~ up to 18.00. Tolerance: +0.015, -0.008.
Diameter: Over 18.00 ~ up to 30.00. Tolerance: +0.017, -0.009.
Diameter: Over 30.00 ~ up to 50.00. Tolerance: +0.021, -0.012.
Diameter: Over 50.00 ~ up to 80.00. Tolerance: +0.025, -0.014.
Diameter: Over 80.00 ~ up to 120.00. Tolerance: +0.029, -0.016.