Source for Small Gear Motors

Hi,

This is a repeat post from the mechanical engineering section, but I am trying to cast a wide net here, so I apologize for the duplication.

I am trying to source a candidate gear motor for one of our products. The basic requirements are:

minimum torque of 6 to 10 in*lbs at the output shaft

Ideal shaft diameter of .250"

100 to 300 RPM at output shaft

Low backlash desirable

Reversible, 12 VDC

Must be a current, commercial off-the-shelf product (not surplus)

The package size is the main problem. If the gear motor is a straight design, then I only have about 2.6" (66mm) of depth available, excluding shaft. The maximum diameter is about 2".

If the gear motor is a right angle design, I have a greater depth to work with, possibly as much as 9" from the center of the right angle shaft. Diameter would be similar in requirement.

This motor can not use a worm gear because the human interface requirement must have the ability for the user to back-drive the motor manually. Basically, the system will either resist user movement (breaking) or augment that movement with an assist, depending on the mode.

Also, if there is anyone here with any design or engineering experience with motor and gearboxes, I will probably have some more design related questions.

Thanks again for any leads or information.