Left hand spiral flute, right hand cutting. Manufactured to BS 122.
INCH TOLERANCES:
Diameter: ~ up to 1/8". Tolerance: High +0.0003, Low -0.0001.
Diameter: Over 1/8" ~ up to 15/64". Tolerance: High +0.0004, Low -0.0002.
Diameter: Over 15/64" ~ up to 3/8". Tolerance: High +0.0005, Low -0.0002.
Diameter: Over 3/8" ~ up to 5/8". Tolerance: High +0.0006, Low -0.0003.