It is a good idea to always read the instructions sent with your order. The Rescue Bit is not your average drill bit and requires careful use. Our tool is designed to run dry, do NOT oil or lubricate the bit. It works best at high speeds for harder metals and slower speeds for softer metals. You may use a corded drill, cordless drill, die grinder, or Dremel (if using in a Dremel please request your tool be broken in half). Also, if using in a hand drill make sure to snug it in the chuck DO NOT tighten it in the chuck! If using in a die grinder, tighten it in the chuck! When using the 3/16" in a die grinder you will need a 3/16" collet adapter. Please remember to not put excessive pressure on the bit and ALWAYS ream in a circular motion during use. If you have any questions at all regarding use, please give us a call/email anytime!