Hehe, I did that with one co workers 12v dewalt. Put my 14.4v in it. It worked fine. Little warmer than before but not hotter then my 14.4 gets anyways. Just from extra power is all. I looked at the motor in mine, upgraded the chuck to dewalt keyless 1/2 inch instead of 3/8ths. Really a jacob chuck. And the motor in mine and his 12v look the same even. I think up to 18v alot of these co's use the same motor. At 18v however it changes cause I tore a 18v Dewalt apart and it has a larger motor, but gear box is same.