The Spear-Zit wood drill bit is a perfect diamond shaped head drill bit, allowing the user to drill at any angle. They are fully guaranteed against breakage and easily fields re-sharpenable with a file. Hint: Use any 3/8' Spear-Zit bit as a pilot bit for hole saws to cut holes from 9/16' to 2 5/8' diameter, through a top or bottom single plate, with an 'up-to-6ft-long' shaft hole saw!!