HHIP 1/4 X 3/8 X 1-1/4 X 3-1/16" 4 Flute M42 Cobalt Fine-Pitch Roughing End Mill Cutting diameter is 1/4". Shank diameter is 3/8". Cutting length is 1-1/4". Overall length is 3-1/16". Ground From Solid M42 Blank. 8% cobalt. Center cutting. Low co-efficient friction. The pressure of the cut is distributed over many teeth. Recommended for high production milling in difficult-to-machine materials such as inconel, hasteloy, titanium alloys and other materials up to RC 40. With a Weldon flat, a flat section on the tool shank, used to hold the tool in place by set screws within the body of the holder.