DC Hobby Motor (130 size, FA-130 / FC-130 etc) mount for interlocking bricks (lego-compatible)

thingiverse

Mount for 130 size motor like FA-130 or FC-130 or the innumerable knockoffs. These are 3-9V direct DC motors popular for hobby use, with a flattened cylindrical profile like the above image. Don't expect to achieve a fit as nice as you get from the official stuff for the top studs and bottom holes (see "print settings"). Some finishing is generally required; see "post printing". You'll want a 4.8mm drill bit or a 3/16" drill bit (4.76mm) if you can't find a 4.8mm for refining the through-holes. I listed some other designs that go well with this part below too, such as "plus axle" adapters for 2mm axles. See "Related Models". ---- Using this in models effectively is not easy! These motors run at high rpm with low torque (typically 9k-12k rpm unloaded, 4k-5k rpm loaded, and 10-20 g*cm torque) and they don't have stall protection. They usually draw 500mA to 1A for startup and stall current and they don't have much cooling so they cook easily when stalled. You will need to make a lego gearbox to go with it that has a large downshift ratio like 10:1 to get sensible torque for most applications. But lego-compatible gears are huge and clunky, and there are not that many good combinations of them for gearbox use. (see [this fantastic article on gear and gearbox design with lego-compatible parts](https://www.clear.rice.edu/elec201/Book/legos.html)). It's fine for bigger models, not so good if you're trying to make little trains/cars/etc. For motor protection I tried a bunch of different approaches with slip drive belts, simple friction clutches etc. But I didn't find anything that would slip when needed but could still deliver satisfying startup torque and avoid slipping during normal operation. A driver IC would be best really, but if you gear it down a buch and put your slip mechanism on the geared-down side you should probably get better results. In the end I landed up switching to ["TT" style gearmotors](https://www.adafruit.com/product/3777) and designing a different adapter for those for my project. I'll link it when uploaded. The TT motors have their own issues though as their form factor is frustrating for use in narrow lego-compatible models like trains.