menthe

New guy with no mechanical experience and no DIY experience hopping into the forum to ask this:
All mentions of cheap DIY electric bikes have said to use a power drill as your motor, which makes sense.
But there's a very similar power tool that is much more powerful while still using roughly the same amount of energy: Impact Drivers.
https://www.youtube.com/watch?v=0URLLgMS5RU
Why not use one of those as your motive force? What damage could it do? Is there some mechanical reason that it simply would not work anywhere near as efficiently?

If you just read the above and wondered "Is this guy ********", don't worry, that's the sort reaction I usually get. Just try to get past it and assume I just don't know any better. Be elitists.

BobV13

No, you don't want to use an impact driver. An impact driver does what is say "Impacts". Not all of the force goes into the rotation of the head of the drill, a portion of the force impacts or hammers.

Ypedal

exactly what he said.

using power tools to drive a bike is generally a bad idea for many reasons.. efficiency being one major factor... 2nd is limited power.. 3rd is range ( a power tool pack would only deliver a couple kms per charge , if that ) and would not last very long as they are meant for low duty cycle vs ebikes that require constant duty ..

possible yes.. not practicle.

menthe

Right, my mistake. It turns out that there are impact DRIVERS, and then there are impact DRILLS. I did not know about this until now.
So what about impact drills, not impact drivers?

sdold

I think the impact drills give intermittent higher torque using a hammering effect, not more power. If I were building something like this I'd want steady torque and a motor with good bearings made to run continuously.

Ypedal

both do the same thing.

difference is in the chuck. the " drill " has a 3 jar adjustable chuck... the driver has a magnetized octogon bit with a locking chuck and you canot put a dill bit into one of those.

menthe

Thanks for the education, guys.

Consider this this thread topic 'solved', in spite of there being no method to note it as such.

Canada Panda

The impact mechanism is separate from the motor so this is irrelevant. However, it's been my experience that impact tools have motors meant for short bursts of power (driving screws into wood or loosening rusted bolts) - my impact drill overheats much faster than my regular drill when used continuously. If you absolutely want to try a power tool e-bike, then my best candidates are motors from a rotary hammer drill or a mixing drill - both are designed for high torque under continuous use. There are better alternatives in DC motors though if you visit an industrial supply shop or possibly even a well-stocked hobby shop.