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Unread 14-01-2010, 01:00
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Tristan Lall Tristan Lall is offline
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FRC #0188 (Woburn Robotics)
 
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Re: pitch of FP motor pinion gear

Quote:
Originally Posted by rc_cola1323 View Post
The DP is 32 on the one AM sells, but the DP on the fp gear in the kop is metric: .8 module.

I would recommend buying the individual AM Planetary for Fp's and integrating them into a gearbox since the one linked above's ratio is off, 6.18:1 . You want a 3.667:1 to match the Cim's free speed.
0.8 (millimetre) module is exactly 31.75 diametral pitch (per inch). You won't have too much trouble making a 32 P gear mesh with that pinion. Many teams have pulled it off without too much trouble.

(Dirty as it is, it's not as impossible as it sounds. In fact, there are a few documented cases of a team managing to make a 0.7 module gear "fit" a 32 pitch pinion—teams 111 and 180, for example.)

Interestingly enough, the Fisher-Price (Johnson) 00968-9015 motor spins at a free speed of 15 700 rev/min, while the CIM FR801-001 spins at a free speed of 5 310 rev/min. The AM Planetary doesn't quite match these based on that speed ratio. (It ought to work, but you might find that the load sharing isn't quite what you'd have otherwise predicted.)