Broken bolt? I recently popped the bolts in a Harmonic Damper while trying to pull it with SAE grade 2 bolts. When the bolt pulled apart it left a very jagged edge which would be impossible to center punch and drill on center. Using a
4-flute mill cutter the size of the tap drill I took the
point off, which presented a relativly flat surface for the
drill. However almost half the bolt diameter was still torn
away.
Solution was to use a drill bushing to keep the drill on center.
http://www.pbase.com/dennygraham/image/161629463/original Needles to say, SAE Grade 8 bolts were used on the next try!
http://www.pbase.com/dennygraham/image/161629486/large Denny Graham
