I'm looking to have multiple motors rotating metal discs at different speeds (each motor would be for a single disc, which weighs maybe 100g and 20cm in diameter), ideally at the pace of a clock (I tried a clock mechanism but it wasn't strong enough to turn the weight of the disc).
The small motors I've found here in NZ seem to be the typical low torque, high speed, but these go much too fast. Initially I thought a potentiometer would do the trick because then I can vary the speeds on each motor/disc pairing, but then though a transistor could possibly achieve the same thing. However, I am brand new to this stuff and am really just fumbling around in the dark.
Short version: How can I best make a small motor that is 11000+rpm rotate as slowly as a clock?