Help! I can’t seem to get my Shapeoko XXL Pro to cut a round circle. The Y axis is not smooth when moving and I’m getting an oval circle and not so square, square. I watched Winston’s Office Hours #13 and cleaned all the belts and pulleys. In addition, I believe all of my belts are tight as he instructed. I can’t figure out by my results of a circle and square are so off. Any input would be greatful.
Have this ever worked correctly?
What sort of toolpath are you cutting?
If your machine is mechanically sound (pulleys secure, belts well-tensioned, linear rails lubricated), check the wiring.
You can verify the electronics by powering down, removing both Y-axis belts (label them so that you can swap them side-for-side and end-for-end), and putting a bit of tape on the pulleys.
Then, power up and connect to the machine and try to initialize — the ma machine will home Z and X as normal, while the Y-axis should turn until it times out — do the two pulleys turn evenly and in synch?
Let us know at support@carbide3d.com
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After you check all your mechanical and they are good then you can do a calibration. The calibration is cutting circles and squares and changing your stepper motor steps to get round circles and square squares. Do not do this until all mechanical things are checked. Since this is a pro have your lubricated your rails? You have to periodically lubricate your rails to keep them running smoothly. Also check the v-wheels and adjust as necessary on the Y rails. If you have loose v-wheels then it can bind. Also check that your machine is square. Jog your machine to the front. Power off your Shapeoko and see if there is an even gap on each side. If the gantry is not square you may need to do a squaring of your machine. Not being square can cause binding when moving in the Y direction.
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Did you check your pulley set screws:
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This is what I do to for a visual check.
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Thank you to everyone that gave me advice. I did follow the advice from this group and checked the pully set screws and it appeared that the one on the right was loose. I also followed advice from the Facebook group and checked to see if both stepper motors were running and if they were calibrated. I removed both belts, left and right from the Y axis and ran an initialization. I found that the left side wasn’t even running. I found that the power connector was barely attached. That’s probably why I was getting intermittent issues. I plugged it back in and tightened the pully screws on the flat part of the spindle and everything is working like a charm. Thanks again everyone!
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Good to hear. The set screw caused me issues around the 3rd or 4th job after I set up my machine. I now check them regularly. But I supposed a dab of lock-tite would be a good option.
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Joe I caution against locktite. Those little set screws would be almost impossible to remove if the head gets stripped with out destroying the pulley and/or stepper motor. Instead replace those as others have suggestedset screws with cap screws.
Ah… and just like that I find tremendous value in being part of this community. Thanks for the message and recommendation. Makes total sense. I think I will order a set of the suggested screws for my next routine maintenance cleaning.
This forum is outstanding in supporting its members. We have everyone from beginners to advanced users. I have other forums I am on and they dont hold a candle to this forum. Ask and you shall receive. Merry Christmas, Ho Ho Ho and a Happy New Year!
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FYI - I used the purple threadlock mentioned in my post - it is the lowest strength and specifically meant for set screws in the description:
It took very little pressure to remove the set screws I put it on when I did upgrade to the larger socket head screws I mentioned. Next I’m going to add a dot to all the v-wheel screws when I replace those over the holiday!
What I learned to not use red threadlock on… laptop screws! I was so tired of them falling out, I put a tiny dot on each screw. I was so sad (or maybe furious) when I need to replace the hard drive a few years later. Drilling out all those tiny screws was…fun. This was before I learned about low strength TL, sometimes (usually?) we learn things the hard way. 
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