Electric drill motors

$15 will get you a crappy, battery-less 12V electric drill. For us, this means a powerful DC motor and gearbox, plus a trigger controller that we can probably hijack and control via Arduino. In other words, perfect if you're willing to shell out $15.

We'll need an encoder, but we can probably do this. One thing I've considered is attaching the encoder to the motor directly, meaning that whatever resolution it has will be multiplied by the gearbox. Thus, a ~32-step encoder would probably be enough. We might even be able to print one with an inkjet printer.

One thing about an electric drill is that while the "low" speed would probably be within one printed gear's range of a "normal stepper speed", the "high" speed would be great for leadscrews and the like -- think LISA Simpson. We could use cheap Home Depot leadscrews, which are too fine for steppers at reasonable speeds.

We could also use threadless leadscrews, and a linear encoder -- digital calipers? But that's a discussion for another thread.

Ever heard of duty cycle, backlash, brushes? Everybody wants a cheap printer. I can sell you a really cheap printer that works much better than anything you can currently build or buy for less than $2000. Give me an order for 1 million of them and 50% down balance on delivery. If you don't believe I can actually do this try pricing Arduinos, Ramps, linear bearings, stepper motors, metal frames at the million piece level.

The secret to cheap and high quality is VOLUME!

So you spend $15 to buy a drill, tear it apart, hack a way for Ardiuno to controll it, and then battle accuracy issues... When you could just buy a $10-15 stepper that you know will plug in and work? Yes, you would have more torque, but we have as much as we need, I have a 1000mm tall delta that runs fine on used $10 steppers.


I get that everyone wants a cheaper way, but when you can buy a used stepper (which work just fine) for $10 each on Ebay, is it really worth all this hassle? Motors consist of about 8% of the printers cost, even if you shave $1 each, you haven't saved any significant amount ($4), and the amount of hassle goes through the roof. It's just not a logical place to save a lot of money.

Frankly, the Reprap community has done quite a good job sourcing parts for cheap, there's really not a lot of places you can trim more than a few dollars here or there without a major re-work. That takes a LOT of time and effort. I'm not saying things can't be done cheaper, but you have to weigh cost vs. hassle vs. quality, so unless there is a major design change, you won't drop the price a significant amount.