[Tom Bottiglieri]

A Fisher Price Motor with stock plastic gearbox SHOULD hold up to your basic arm needs. This is relative to what you are doing, though. If you are trying to pick up 60 pounds on an arm with a 60" swing, with no reduction to the rotation axle, you will stall the motor, probably smoking it, and possibly grinding the gears inside the plastic gearbox.

I recommend using JV N's motor calculator to find out how much torque your arm requires, then choosing the motor in the kit with the corresponding peak power.

(For reference, many teams were able to hang 130 pound robots off a FP motor with stock gearbox, without killing the motor or the gears.)

My opinion is.. make sure you need the power of the FP first. If you dont, opt for the van door. It is more reliable and not as picky as the FP. But, if it turns out you need the FP, make sure you give yourself about a week of testing on the arm. Then you can find any quirks, and see if something will go wrong. If the motor overheating becomes a problem, limit the voltage to about 9.6 - 10.5 volts. If the gearbox begins to grind, fabricate your own, using either nylon or aluminum side plates, and gears ordered off the INTERNET. You can construct this gearbox in any high school machine shop. If needed, post or search to get info about making your own custom FP gearbox.