I have a very old tin-record music box. The motor is missing (used to be a wind-up spring motor). I'm thinking I might be able to use an electric motor of some sort(plugging it into the wall socket) and maybe some sort of controller mechanism to slow the thing down. The old tin record needs to spin at no more than 2 or perhaps 3 RPM. I realize I can cheaply purchase a DC electric motor, but I have no idea how to slow down the RPMs to a crawl without the thing burning out. Any ideas? Does some company sell very slow adjustable RPM electric motors? I don't need anything powerful, it must plug into the house sockets, and it needs to be only 3 or 4" in height max in order to fit into the old box, and it will need some sort of protruding 1/4" thick or less spinning rod so I can attach the small mechanism on which the tin record rests. Thanks for any ideas.

Not sure exactly of the specifics, but it sounds like a "gear reduction box" may work. You may find something that works from a clock repair shop, if there's one local, bring it in to them. They have all kinds of different gears and mechanisms that may work. Or an RC car and or hobby shop, they sell many different small motors for these samll remote controlled cars.