Does anybody know if the Fisher Price motors included in the 2012 Rookie KOP (with pinion attached) will fit in the AndyMark GEM gearbox (am-0449)?
I don’t believe it will. The pinion on the FP motor has a DP (Diametric Pitch) of 32.
AndyMark’s website says its internal gears are 20 DP.
http://www.andymark.com/product-p/am-0449.htm
ALSO: The sun gear for the GEM is 15T, while the pinion is 13T.
If you want to use an FP with the GEM gearbox, you’d need to use the CIM-SIM or the AM Planetary to “convert” the gearbox output to a CIM.
I imagine you could actually do something similar to the AM Planetary conversion. Buy the right sun gear to press onto the FP and make a mounting plate that will give you the CIM’s bolt holes. Unless there is some limitation on speed or torque you can input into the GEM, I don’t see why this kind of thing isn’t possible.
The AM Planetary output is the CIM input size. Since the AM Planetary has the same ratio, why wouldn’t you use that?
This is certainly a valid method, but not useful if you don’t want to convert your FP to a CIM, i.e. you want to use the GEM directly with the speeds and torques that the FP normally outputs, not something geared to replicate a CIM.
Same ratio as what? If you wanted to use the 3.67:1 ratio of a GEM 500 gearbox with an FP, it wouldn’t be very helpful to put an AM Planetary in between (now you have ~10:1 ratio).
The AM Planetary also has a 3.67:1 ratio. Different gear sizing, same reduction.
Oh, I see what you mean. :o
I think the OP needs to tell us why the GEM is being considered…
We would like to gear the FP down to ~5000 rpm for use in a shooter. The AM planetary has the same reduction as the GEM – unfortunately, it’s currently out of stock.