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Pinning
If you don't have a broach tool, you can pin the gear to the shaft. However, you should use a bigger shaft than 1/4.
Here's a simple way to pin a shaft using a drill, a tap, and a set screw (contrary to what Woody said, set screws can be useful as pins -- I just wouldn't use them as set screws):
1. Put the gear onto the shaft in the location that you want it to be (you might want to hold it still with some clips or something).
2. Drill through the gear hub and through the shaft being sure that the drill hole goes into the shaft symmetrically (ie through the center line).
3. Leaving the gear on the shaft, tap the hole to the thread of a 1/8" diameter set screw (I can't remember what the thread is off hand. Be sure in step 2 to select the proper drill for your set screw diameter and thread). You'll want to leave the gear on the shaft when you tap so the threads go seamlessly from the gear to the shaft.
4. Turn in your set screw so that half of it is in the shaft, and half of it is in the gear. You might want to use a little Loctite to keep the screw from coming out.
That is a pretty simple way to do it. You can hold quite a bit of torque with a pin this way. You can calculate the shear stress in the pin very easily and use a material table to determine if you'll fail or not.
I would not pin the final stagegs of your drive train, but the torque at the output of the Chiaphua motor can be easily handled by a pin.
-Chris
Last edited by Chris Hibner : 25-01-2002 at 15:27.
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