Drilling the bolt really isn't necessary- - - -just put a deep groove with a 3-cornered file or a Dremel tool cutoff wheel in the threads from top to bottom. It doesn't hurt the strength of the thread and it's simpler than drilling.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!