1/4 X 9/32" High Speed Steel 3 Flute Solid Pilot Counterbore ~ Cutter diameter is 13/32". ~ Shank diameter is 3/8". ~ Overall length is 3". ~ Continuous pilot counterbores cut rapidly, smoothly and accurately, producing long spiraling chips rather than small metal particles. ~ The pilot extends the full length of the flute portion of the tool. ~ As cutter flutes are ground back due to wear, a new section of pilot becomes exposed. ~ The pilot head may be cut off to any desired length when repeated sharpening makes it too long for practical use. ~ Continuous pilot counterbores have a life many times that of the conventional type counterbore. ~ Cap Screw is 1/4". ~ Pilot Diameter is 9/32".