modern metal working shops and cnc machines need a steady supply of accurately sharpened high speed steel, cobalt, and parabolic flute drills. in meeting this need, over 40,000 shops have found that black diamond precision drill grinders are the most reliable and economical way to sharpen all types of drills to manufacturer's exact specifications. black diamond machines exceed the performance of drill grinders costing twice as much and no other machine in their price range can match their consistent accuracy, and ease of use. because no set-up is required, the black diamond is fast, easy and foolproof. simple adjustments for relief and included angles consistently produce drills suitable for accurate, high quality work and long life. only black diamond machines are equipped with precision collets for each drill size. and the easy-to-use, fully adjustable web splitting feature works without removing the drill from the holding fixture.