A customer brought in an older B&D rechargeable screwdriver looking for a battery. We told him we didn't have such a cell, but we did have a whole new driver. He bought it, and I asked him what he was going to do with the old one. his wife said he was going to toss it. I asked if I could have it - that I did crazy little projects and might be able to do something with it. He let me have it.
I figured out how to disassemble the thing, and removed the rechargeable pack. It was a 3.7 volt motor - figured 4.5 volts (three AA batteries) wouldn't harm it. If it burned out, no big loss. Cleaned up all the tiny contacts and the switch, and soldered in a triple AA battery holder. With some careful dremelling of some internal gusseting I got it to fit back together.
And man is that thing handy! It's not fast or very high torque, but on many jobs when I need an extra set of hands being able to push a button will work when twisting a regular driver won't. Love it!
