Mounting the Fisher Price Motor


Hi all,

My team and I are looking to modify our arm for lowering the Rebound Rumble bridge. We’ve been looking into other solutions, and the Fisher Price is a candidate, except for one major problem: how do you mount the motor? There appears no obvious method or place to connect the motor to the part or the robot, and research has had no answers.

Is there a method of doing this that we’ve missed or neglected in reading?

Katelin from FRC 1369 Minotaur


Are there not screw holes on the face of the motor?


Could you post a picture of your setup?

I take it, your wanting a way to mount the motor with a gearbox to your assembly?



if you post a picture I can validate this, however I believe I know what you are talking about. If I recall correctly (if you have a gearbox) you can cut a piece of aluminum c channel down to two inches (maybe 2.5) find a center line after cutting off one side of the c channel and from the center line, go about .5 inches out, and mark two lines (one from both side) I believe the firth hole should be some weird 7/16 away from the now only remaining wall of the c channel, and the second, (again, assuming a gearbox [we used a 4:1]) can be measured. holes shopuld be marked half an inch from the center and drilled using .25in drill bit. (I made about 8 of these in the during the build season)

good luck-

If you post a picture, I can validate this.



Here are three images that show how we mounted and use the FP motor and transmission to move our arm in 2011.

The interface for the output of the transmission is detailed in this post.

It uses 10 7/16" diameter holes on a 1.75" diameter hole circle.
The center shaft configuration is up to you. In 2011 we used a 1/2" axle that was threaded and cross drilled and bolted in place.
This year we built two more that used 3/8" axles that were simply cross drilled and pined in place.


If you don’t want to or can’t make the adapters to interface with the output, use this.


If I had a picture on hand I would show you but these work amazing. We used one for our bridge manipulator this year and the C-channel bent before this adapter broke.


Yep, that’s what we did this season for the bridge arm. Makes it super simple!


In 2011, we used 2 of them (2 motors, one gearbox per motor, linked by a common shaft) and we lifted the robot, bent a 3/8 inch solid aluminum shaft, and fracture a #35, 12-tooth steel sprocket (in three places) all at the same time, the gearboxes and the adapters were completely unaffected.


Although some of this discussion seems to have centered on mounting the FP gearbox, there are also a number of ways to mount the motor directly. The face of the motor includes two metric taped holes, which can be used to do a face mount of the motor. If you do chose to do a face mount, keep in mind that on a FP motor, it is extremely important to keep the ventilation holes in the face open (FPs are very prone to overheating). And, if you don’t mind pressing the pinion on the shaft of the motor after installing it, you can make a hole that is a press fit for the hub on the face of the motor.


Thanks for all of the help. We’ve drilled out the three hole, and we’re currently designing a bracket for fabrication and attachment at the next meeting. I’ll try to post pictures when we’re finished and we know it works.