I found another couple of battery drills being thrown out last week. One Power Devil and one McKeller.
The Power Devil is the usual bottom-rung battery drill, though looks like it’s been fitted with a replacement chuck.
I opened up the battery pack, and it was pretty much what I expected.
The McKeller on the other hand was much nicer and more powerful. However neither drill had a charger unit, so they’ve both been stripped down to motor and gearbox. I’m thinking they could be good for making a reasonably powerful robot arm.
The chucks on all of them attach with a 24tpi UNF thread. I might have to belt-gear them down, but then again PWM control would probably be fine and simpler to attach.