Center Drills are used with the lathe to center drill stock for mounting in the lathe. They are designed to drill a small diameter pilot hole followed by a 60° countersink which provides a bearing surface for the 60° point of the lathe center. Center drills are also used extensively with the milling machine to accurately start holes. The hole locations can be dialed in using the milling machine's calibrated handwheels. Then the hole is started using the center drill. The large diameter shank on the center drill holds the drill point right on center. Once the hole is started, the center drill is replaced with a drill of the desired diameter and the hole is finished. It is imperative that a cutting lubricant be used and the center drill is backed off several times to prevent the tip from twisting off.
This center drill set consists of a #1, #2 and #3 double-ended high speed steel drill. The #1 has a 1/8" shank, the #2 drill has a 3/16" shank and the #3 drill has a 1/4" shank. The tip diameter of the #1 is .047", the #2 is .078" and the #3 is .109". Other sizes are available upon request. Return to Lathe Accessories Section