adapting the fisherprice gearbox

[thefro526]

Originally Posted by s_forbes

We've used some pinions from the RC car market to fit these types of motors for 32p applications. We have yet to use one in a high torque application though... mostly just for high rpm shooting type mechanisms.

Something like this might fit the description you posted above.

They come in an array of tooth counts and bore sizes, and are pretty inexpensive compared to other mechanical off the shelf parts. Maybe someone with more experience from the RC background can chime in.

I've actually got an array of 32DP Pinions from a few different RC car manufacturers floating around somewhere.

We ran (2) different sizes of Robinson racing pinions (23T, 17T) on our revised shooter in 2013, and found that they don't like to be run with just the set screw alone to retain the pinion. After losing a pinion along the way (It might have been during testing, it's been a while) we started to apply a drop of loctite 609 to the pinion's bore prior to installation, and then tightening the setscrew as normal. We also swapped the set screws to cupped-end screws, IIRC, and haven't lost a pinion after 3 Off-Seasons, a dozen or so matches at the CMP and a bunch of demo stuff.

Our revised Arm transmission ran this guy from AM: http://www.andymark.com/product-p/am-0896.htm which has a 6-32 set screw compare to the #5 set screws in a lot of RC-Car pinions. After numerous burned out motors, 5 or 6 events of abuse, I've never seen one of these slip, and I'd imagine that if it were going to slip, a 550 at stall would do the trick.

Also, AM actually stocks the 'standard' 19T pinion used in some FP Transmissions, so if you really wanted to, you could use that one with the AM-9015 and shouldn't have any problems: http://www.andymark.com/product-p/am-0604.html If I remember correctly, that pinion has a .125" bore, and doesn't like to seat on RS550's without a bit of help. As I said above, an RS550 has a 3mm output shaft, which measures out to be something like .118", so there's about .005 - .007" of play between the .125" pinion bore, and the RS550 shaft, which is enough to ruin any shot at a good press fit. In 2012, the team I was with used loctite 609 to fill the gap, but it wasn't an ideal solution by any means.