The general rule of thumb is to replace drums if they're .090" over standard diameter. You might get away with .125" over (1/8") if you can get any machine shop to turn them that far. Most won't because they're violating federal laws (DOT rules) if they do. Nobody is going to put his business at risk so you don't have to pony up for new drums.
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!