With the incorporation of more Jimi Hendrix songs into his set, Stevie Ray Vaughan decided to tune his guitar down a half step all of the time, just as Hendrix had done. Detuning the instrument facilitated the move to even heavier string gauges, all the way to .013s, several steps thicker than the norm. Detuning serves to decrease the tension and make the heavy strings easier to bend while yielding a better tone and a meatier sound. Playing them required enormous hand and arm strength and a level of sacrifice in terms of ripping up his fingertips that few would be willing to embrace.
Doyle Bramhall II: He paid a price for being as committed as he was to the kind of string bending he was known for. He had a “callus kit” to make new calluses on the spot: a wallet with compartments for nail files, manicure scissors, super glue, and baking soda. He often had massive holes, like a quarter-inch deep, in his fingertips. Before shows, he would fill the holes with baking soda and put super glue over it and stick it to the other palm of his hand let it dry and rip a new piece of skin off to form the new callus. Then he’d file it down smooth so it wouldn’t catch on the strings. He was very ingenious and inventive.
Source: Texas Flood: The Inside Story of Stevie Ray Vaughan by Alan Paul & Andy Aledort
