The essential part of any brake drum is its ability to transfer heat, evenly and rapidly from the friction surface where the linings contact it to the outside of the drum where the airflow over the drum can blow it away. I'd be a little reluctant to bet my life on something that had been built up and re-machined to have the same thermal transfer characteristics as an original, unmodified drum. I've heard on several occasions that an average stop from 60 MPH generates and transfers enough heat to melt a 9 inch cast iron skillet. The reason the drums don't overheat and/or melt is the incredible ability of that same cast iron to dissipate the heat to the surrounding air. That's why painting or powder-coating drums is such a dumb idea!
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!