Today for a friend I removed a 5/16 - 18 bolt he broke off when he was installing the clutch on the flywheel in an old Ford car he's fixing up. He figures the bolt was a tad too long and since Ford didn't tap the hole through completely, it ran out of thread, jammed up and SNAP! Naturally he had tried drilling it and using easy outs to remove it so it was really a mess from the bolt head side but fortunately from the back side I had a pristine hole to center under my mill's spindle. Once all lined up I bored it out with a sharp 1/4" end mill instead of a drill bit so it wouldn't walk sideways any when it got into the part he had drilled crooked. After that I tried a tap and it actually picked up the original thread so, with care, that's how the threads were cleaned out. It worked like a charm and this time all the holes were threaded completely through...just in case!

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