Easy to work- Attaching the deburring external chamfer tool to the end of your power drill, Use the lowest speed on the drill bit, and then slightly applying pressure to remove the burr. Cost-Effective- These deburring external chamfer tool can be used for repairing damaged bolt and tightening the nuts in place. You do not need to spend time and money to find hard-to-find or expensive replacement bolts. Safety Design- Quickly repairs damaged bolts and tightens the nuts in place without hurting your hand, no sparks, and no burns; Simplifies the repair process. Using proper speeds and feeds-Drill use 0-400 RPMs. Fit 1/8' (3mm) to 3/4' (19mm) Widely Application-Effectively used in Stainless Steel, Hardened Steel, Mild Steel, Copper, Brass, Aluminum, Fiberglass, Wood, Plastic