I have a power screwdriver which I found quite useful when I have a lot of screws to turn. However, it uses 4 AA batteries for its power. The recommendation from the manufacturer was to use long lasting heavy duty alkaline batteries. In my effort to try to get more useful work out from the tool, I had tried to use rechargeable Ni-Cad batteries so that I could recharge them. It worked for a while, but after some time, the rechargeable batteries themselves became faulty.
Since I had made a variable voltage power supply for my workshop, I decided to connect it to my power screwdriver. I felt it made sense, since I did most of my work in my workshop. Still, if I ever need to be portable, I could obtain some AA batteries and it would still work.
The concept was very simple. Just solder 2 wires to the terminals of the battery holder and connect the same voltage (6V) from an external source to power the screwdriver. The external source would be my mains powered variable power supply unit which I had installed at my workshop. A long wire would ensure that I would be able to reach a distance that I had wanted.
The challenge was to dismantle and modify the screwdriver. I had wanted to maintain the placement of the battery compartment, so I had to poke the wires out from the sides. I figured out that if the wires were to poke out at the end of the screwdriver, it would disturb me when I wanted to exert some axial force by the palm of my hand. By placing the wires at the side, it would look not so nice, but would be more useful as a tool.
I used thick single core wires since they were not supposed to be flexible. They will be more robust that multi-strand wires.