using a wire through the hole in the housing and through the spring for positive? One of the industrial line lasers i have her that i raided for parts and adventure, used pieces of foam to locate its driver in the center of its host, one on each side of a cylindrical housing. The unit is a laser blazer, a line projecting laser that came off a giant saw. I have hooked it up to my test load just to play with its pot, the most i can get out of it is around 20mw, using the 5v ac adapter for power. If i could find one of the larger diameter diodes, it has a threaded lock ring for holding the diode in its heatsink, im waiting on a pair of 14500s now to make a neat host, it still has all its stickers!! (using 1 14500)