Most of us, especially pre-Millennials- in the aeromodeling hobby are accustomed to frequenting a handful of traditional distributors for flight hardware - Tower Hobbies, Hobby Lobby (now Hobby Express), Brodak, Sig, Hobby People, Horizon Hobby, etc. Except for lines of proprietary kits, motors, and equipment, most offer the same assortment of goods. That's fine if you are building and/or flying standard models with standard parts. If, however, you are one of the precious few modelers these days who builds and operates unique models with special needs, as with scale, research, or ad hoc experimentation, then you may be frustrated with the normal suppliers.
Fortunately for you, there is a whole separate world of people who need and use components similar to ours, but with different form factors, sizes, and specifications - the robot crowd. The next time you are looking for a custom gear set for a set of retractable landing gear, gun turret rotator, bomb dropping mechanism, or canopy opener/closer, search for robot component distributors. A couple particularly popular sources are Servo City and Robot Shop. As the names imply, they have huge stocks of gear boxes, servos, stepper motors, controllers, bearings, shafts, batteries, wheels, axels, switches, collars, lights, speakers, RC gear, sensors, range finders, microphones, wire, connectors, and host of other neat-o things that will cause you to ask how you could have missed such a cornucopia of modeling wonders before. There are of course many other sources that a Google search will turn up.
Posted July 25, 2015