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Topic: Can I fix this stepper easily? (Read 213 times) previous topic - next topic


Hey, during one of my recent 3d prints the extruder motor system clogged up and the stepper promptly ceased to move filament.

The stepper still makes the correct noise and moves, but there is no output from the gear box on top of it. This is what the gearbox looks like now - minus the planetary gears because they are all in good shape:

As you can see, the sun gear rotates around and slides off the axle easily. The axles still outputs power, so I know the problem is from the sun to the planetary gears. Now, I'm guessing the sun was pressure fit? Or welded, or something. Whatever the case, I know it should be attached to the axis. Since it slides around now, do I have any hope of fixing it?



Jul 16, 2017, 12:42 am Last Edit: Jul 16, 2017, 12:47 am by larryd
Get a piece of shim stock and press fit the gear on the shaft.
Use Loctite Red 271


No technical PMs.
The last thing you did is where you should start looking.


Probably not, but is there a set screw in the gear under the grease?


Well it certainly wasn't welded if its spinning freely now!  Probably a poor interference fit and the combination
of overload and the grease has allowed it to turn and polish the roughness the fit was relying on.

If the pinion has no grubscrew your best bet is probably spot-welding at the end of the shaft and pinion,
if you have access to suitably rated equipment (this is quite fine work for welding).

Both shaft and pinion are likely to be hardened which limits the other options.  The pinion appears to
be shouldeless so there's no way to use a roll-pin or add a grubscrew I suspect.
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]


Both shaft and pinion are likely to be hardened which limits the other options.

Two or three hours spent thinking and reading documentation solves most programming problems.

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