X-pulley issue on Shapeoko Pro

After a couple of months of running the Shapeoko pro (XL) I ran into an issue with one of cuts, the bit drove down into the wood because I had not tightened it hard enough .
Anyhow my Shapeoko no longer works - it can’t even home it. I’m pretty sure the X-pulley came loose and is spinning (though I cant remove it yet, waiting for a gear extractor). Looking at past topics on this issue looks like there are two solutions for this:

  1. Flip the pulley so the grub screw connects to the flat part at the top of the shaft. Easy solution but concern this moves the pulley further out and maybe bending the stepper motor axle in the long term ?

  2. Filing part of the axle flat for the grub screw.

So my question is , between these two solutions which one is recommended ?

Would you clarify this, please? I understand the bit cut too deep into the stock, but I’m not sure what you mean by “…I had not tightened it enough”. Are you referring to the stock or the bit not being tight?

I’m not sure if this could be related to the other, random, deeper-than-expected cuts.


Seems clear, Peter. No conspiracy here :slight_smile:

So I had not tightened the bit hard enough in the collet which caused the bit the drive into the wood. Unfortunately this is not the first time this has happened so well aware of this particular issue, just wanted to give some background of what happened before my Shapeoko stopped working.

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So, I guess you’ve seen this post then with the inverted pulley ?

I’m not sure you need a gear puller, but if you’ve ordered one anyway it won’t hurt. Do be careful with the thin lip end of the pulley, these are generally pressed on and come off quite easily.

Although you’re right to worry about moving the load point further down the stepper shaft, inverting the pulley is not going to significantly change the load point. The inner round face of the pulley sits on the shaft so the loads should still be applied approximately where the belt tension is centered.

As for filing the shaft, I would not do that, it will definitely weaken the shaft and make it more prone to a fracture failure later on (which is a known issue).


I love our British sense of humour, @Gerry :rofl:

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There is no need to flip the pulley. The set screws can hit the flat with no problem. It simply may need to rotate on the shaft to be in the correct position.

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