Folks,

I have a Graupner Speed 400 and a 3.6:1 Graupner gear box with it. This is my first RC project, so I am at a bit of a loss here.

I have the motor, a brass gear that would sort of fit onto the motor shaft, and the gear box. My question is, how do I join my brass gear with the motor shaft. It seems to be a very tight fit, and I am hesitant to use a hammer or so to force the gear onto the shaft. In addition, am I supposed to epoxy the gear to the shaft?

Thanks in advance for your suggestions.

The way I did mine was to measure the depth the shaft will go in but not touch the back side of the driven gear(used calipers) the shaft was shortened to 3/8" so the motor could be pushed all the way in...I made a special pinion press out of a c-clamp(there are commercially available ones but I like to do my own thing)and just twisted it right on flush to the end of the shaft. Check the req. len. of the shaft twice before you cut it, just to make sure. The pinion hole might be chamfered on one side, if so , start it on the shaft from that side, the press fit is tight enough so no solder or locktite should be req. Don't forget to de-burr the end of the shaft so the end doesn't dig in to the gear hole, also , you might want to mask off the bushing, so you don't get steel grindings in it...Good Luck...

The pinion must be pressed or driven on. However, don't go banging away on the gear with a hammer, or go squashing the motor in a vise. Either one will destroy the motor's bushings. You need to support the gear shaft of the motor, not the motor body to install pinions.

What I usually do is drill a hole in a chunk of wood to hold the pinion. I then stick the motor shaft into the pinion as far as it will go easily. Then, using a hammer and punch, I gently tap on the back end of the motor shaft to finish installing the pinion.

There is another way. Cool down the shaft of the motor and warm up the pinion. Then you can drive it on the shaft. After reaching room temperature it should be unmoveable. We use it with nearly all gears and other problems (Forks of Mountainbikes).

MfG,
Armin

got it! and the motor still works

I used mkirsch's suggestion this time. I had thought about heating up the pinion as well, will try that approach next time.

Thanks everyone!