Zero Moves After Pause/Stop of a Program and Rehoming

Its not how they say to install, but even the new belt slipped some if you put any tension on it, this way it locks in tight and the belts do not slide in the clamp. And no issues in the function so win win… I did calibration test cuts and zero sets and it is back to where it was when I got the Pro all setup.

If you tug on your belts a but by hand watch the clamp area, I bet you can see it slip and loose tension, it has bugged me since the start, they need a better setup that can be tensioned and hold tight IMHO.


Sounds like your belt clips might be a bit funky, they’re meant to pinch the belt tooth to tooth under the clamp once tightened up I believe. I’ve had mine slip whilst initially tightening the clamps but not once done up.

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I bet if you tug a bit on them they will slip, might be some funky early Pro versions, but you can see if slip just a bit at a time, original belts, after use, and new ones… So this seems to have fixed it, I will see after hours of cutting I guess. I will let everyone know

What’s funny is my machine is less than a month old and I’m having the same problem with the belts slipping out. Trying to get enough tension on them is really hard because by the time I try to tighten them up they start slipping back out. I wish carbide would switch to a tension knob and have the belts run through the end plates. That concept has become super common on 3d printers and it works much better at dialing in tension

Try the way I ran the belts, you also can use a small pry bar to get even pressure on the clamp to get the bolt started, you will be surprised, I am so far loving it, I have pushed the machine faster and it has less issues so far. Tomorrow I need to run some production aluminum so I can compare to past runs and see if I can push it harder.

There are some community fixes that you could 3D print (or machine) and try out variations of

I printed a set of these and apparently the worked pretty well, I’m sure the design is adapatable to the 15mm belt relatively easily.


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@Brasch I have nothing to add to the convo, but I saw your post on reddit and I need to know more about this car with mosaic tile installed in it!!!

I own a business that makes custom parts and interiors for old Porsche and other custom cars. The Picts on Reddit are of a new key surround we are testing on my 1972 911. You can see our parts and interiors here Http://


Liam, thanks for the link, they look interesting, my simple fix seems to stop all the slipping I had

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The image of your belt clips also looked off to me, so I compared to my S03 setup.


Yes it is different than what you have, as I stated above the only way to get them from not slipping even a little bit. Am I opinion for wood it probably doesn’t matter when you start cutting aluminum and you’re pushing hard I noticed belt tension shifting. I’ve been cutting now all day yesterday edit it is working great


Cutting great with a .08 step over and 0.12 depth of cut. Just hogging out material now


All, if you are having similar issues, please check that the Y motors are solid when the machine powers up. An issue with my Bitsetter and bitrunner required a new Pro Mother board and when we were testing the right Y motor control was not working, there was some play on power up. With the new board the Pro is running like a champ and I am able to push and get solid results still…

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I’m still seeing a shift in the zero position after rehoming, new mother board and bit setter, but still shifts by a bit on the y if I rehome, anyone have any ideas why??

How much of a shift? The homing switches don’t have perfect reproducibility, if you are doing precision work you should re-zero after homing.

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Things which will help make the Y-axis more consistent:

  • pull the gantry tight against the front endplates and hold it there when powering up
  • ensure Y-axis belt tension is even
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Will I’ve done all that, it’s off by about .25mm to 1.5mm on the Y inconsistently after it rehomes and I’m cutting aluminum. The zero coordinates don’t change in the system but it’s off. And with aluminum, it’s noticeable with crashes or bad secondary cuts, I was hoping the new board would have changed something. The belts are new and consistent, always start with it pulled up front, etc.

Do the limit switches need to be adjusted?

Most interesting is I was cutting some 1 inch exact blocks for a jig out of half inch aluminum, and without rehoming they were within .001 accuracy. So the machines capable, I’m just chase in the rehoming because it’s hard to tell if it’s off by a half a millimeter or a quarter millimeter even checking the zero. And then it ruins a part

Please let us know about this at and we will do our best to work through this with you.

If I have to rehome my machine during certain operations, like a trace or finishing operation, I generally end up scraping the part. I can confirm and rezero if necessary, but things may be marginally askew. Repeatability may have decreased after switching mechanical switches to proximity.

I suspect you could dial it in a little, but I am not sure how persistent it would be. Loading and unloading machine. Moving the machine slightly on its table ect.

Some 3D printers and entry level stepper driven CNC machines overcome this issue by skipping limit switches all together, instead relying on hard stops and electrical feedback from the stepper