[Alex.Norton]

True, in the case of a FIRST robot, there is little problem with tying the worm drive motors together. A FIRST robot is not going to see even hundreds of hours work and the problems with this set up will not be evident.

Another reason that this may not be as much of a problem is that the motors aren't working at their max speed and so aren't back driving each other. If your not going to run this for a very long time then I would suggest this, its simple easy and probably not going to fail. If you intend to use this for years to come as a recruitment tool or demonstration tool, I would suggest using a worm gear motor with, say, a globe.

Also, as a side not the keyang motor is easily backdriveable. We had to provide the motor with a holding power to keep it from falling. I haven't used the nippon-denso motor yet and do not know if it is like the keyang motor.

Thanks for the correction.