This 224:1 gearmotor is very comparable to a hobby servo for power, at a fraction of the cost!
Solarbotics is the sole commercial outlet for these impressive 224:1 gearmotors. They are very comparable to a hobby servo for power, at a fraction of the cost!
This motor offers 48.6 in*oz of torque at 3V, rotating 360 degrees every 1.5 seconds (24 rpm - just a hair slower than a servo), drawing 400mA at stall (free running at 40mA).
With a 7mm double-flat output shaft (avoid using the "D" output - it's not meant to take rotational load), and a built-in clutch (limiting at 60 in*oz, but easily "locked"), and built-in mounting screw holes, you can see why we like these motors!
These units have an overall size of 55mm (2.17") x 48mm (1.89") x 22.7mm (0.894") thick, while only weighing 31.4 grams or 1.11 ounces.
Based on the original design by Mark Tilden for use in the B.I.O.Bugs & RoboSapien, these motors are the next generation with a variety of improvements such as dual output shafts and a lower current motor.
Check out this quick tutorial for how to modify the GM2 from a torquey slow 224:1 ratio to a speedy 14:1 ratio.
Do you need to mount something to the shaft of the motor? Try the GMW - it's a very effective platform for a variety uses. Alternatively, you'll also find that a #2x1/4" SMS screw will provide a snug fit for your need.
(Motors are sold individually, wheels are not included)