I had to Drill and Tap 6 of those mother*&%$. I drilled out with as large as a drill bit as I could manage, then the ez-out was bigger and actually deformed what was left to make removal easier... I would also recommend a bottom tap to chase the threads afterwards...Yes they are hardened bolts and "special" so the woodworking drill bits barely scratch them, need the good steel drill bit. doesn't hurt to smack the bolt with a hammer also, helps loosen up the corrosion in the threads also.
Sheared Bolts Crank.jpg
This was the aftermath of turning 8000 RPM with a Cast Iron Flywheel...the rev limiter is set a 7500 now and using a aluminum Flywheel.
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