For the past five years, I've been maintaining a bicycle with parts I've recovered from dumpsters and yard-sale-give-aways... i.e., anything that's free.

During this time, I've also accumulated three of those little electric scooters - the kind that you stand on, but has handlebars to steer (back in the day, we had to push these with one foot, like a skateboard).

I've resolve almost all of the mental design obstacles for transferring the electric motor from a scooter to my bicycle (e.g, it turns out that all of the electric motors I've accumulated are, indeed, reversible - thus they can be right or left side drive), but I'm now at a point that it requires some modifications that I cannot make on my own - welding, for example... and a machinist to make a custom sprocket. And, the last piece of the puzzle for this project will be the "throttle" (rheostatic speed controller)

Is there a subreddit where I can discuss this (e.g., with machinists, mechanical/electrical engineers, etc.) and help me over these final few hurdles?