Centering a drill bit is always the toughest part of drilling a broken bolt. An off-center drill hole causes the surrounding threads to be ruined. With Quikcenter the drill is perfectly centered in the broken bolt so you can step up to larger drill bits until the bolt is drilled out so thin that it will fall out of the hole leaving the threads intact. Then I run a tap through the hole to make sure it is clean. The original threads are ready to use again. I got mine from www.quikcenter.com and wanted to share for anyone with a similar problem. It’s a must-have for every mechanic and hobbyist & its very affordable.