Bolt extraction using a Left handed drill bit! When a bolt breaks from over tightening often times the broken bolt will come out with little to no effort, assuming the threads are still in good shape. When the head of the bolt breaks off the stretch/tension on the threads disappears. A great tool to try 1st is a LH drill bit, you'll also need a reversible variable speed drill. To make the most of the LH bit and increase its chances of grabbing and removing the bolt here are some tips. -Center pu