Z axis keeps stalling going up - Solved

Hi, my Z axis keeps stalling, only near the bottom of travel and only going up. I’ve loosened the ball screw to a little over a thousandth of lash, which is about what I’d like and more than the other axis, which did seem to help a little. Since it’s up only it feels like it just doesn’t have the power, not something binding. :man_shrugging::man_shrugging:

Does it make added noise? Mine was stuttering and at a faster rate would move but not the slow rate necessary during cutting. And it made considerable noise. I thought it was the other Y-axis screws. It took a bit to isolate. It turned out a little lubrication on the screw was all it required.

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Just makes the stalled stepper noise like when you hit the hard limits in some of the assembly steps. I’ll check the lubrication tomorrow, but everything else has been very well lubed from Langmuir though.

i dont have mine together yet, but on my other cnc when i have issues like this i like to manually turn the stepper to see if i can feel resistance. and or remove the lead nut to push the gantry up and down to see how it feels

I had that pretty bad when I assembled my machine at first, but my z-axis shimming was also pretty off from the online calculator, after I re-did the shimming, I was able to tighten the nut back up. Not sure if it was making it bind or what, but it seems fixed now? My thought was that if the added force of slight binding was enough in combination with the effort to lift the head, that it might overcome the stepper vs going down.

btw, cool to see others from Tacoma on here!


Been having similar problems. Only mine on the X direction. It seems the hard stop threshold is too low?
Mine does it every morning coming off the home position. I’ll run it back and forth several times and it works all day for now. I believe the new CutControl version will address this. Hopefully soon.

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Mine does the same if I try to run a high Z rapid speed. I had to run the screw nut backed all the way off (so bearing could be rotated) so that it would finally move upward. Mostly when machine is cold; seems to have gotten a little better. I’ve been able to take most of the lash out, but I’m still a bit nervous it is going to skip steps during an operation and ruin a part or endmill. Langmuir cited tight lead screw nut and that it should loosen with use.

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Just a heads up on this issue; we have started shipping all new machines from here on out using the high powered driver on the Z-axis (instead of the X-axis) based on feedback we’re seeing in the field. We are going to release a PDF of simple instructions for current customers to make the wiring swap inside their own electronics boxes if they choose to make the modification. Below are some quick points.

  • The Z-axis lead nut uses a heavy spring on the anti-backlash leadnut and also has a tight fitting thread on the ACME lead screw. We do this to ensure that backlash in Z is kept at a minimum for accuracy and floor finishing purposes which are very important for milling. Over time, this tight system breaks in better and the standard Z-axis driver has proven adequate for operation, even at rapids. That being said, any lost motion on the Z-axis has the greatest chance of causing damage to the machine itself (such as a vise or baseplate if the Z axis position gets off during a program) and we’ve decided that the high powered driver on Z provides significantly more margin for the broader customer base.
  • We’ve had a half dozen folks with stalling issues on the Z-axis that have reached out to us. Switching to the larger driver has immediately solved these issues. We’ve never seen a stall event on the Z-axis on our own machines using the High Powered Z-axis Driver.
  • Swapping the large driver inside the electronics cabinet from the X-axis over to the Z-axis means that the X-axis will use the standard sized driver moving forward. In all the years of testing that we’ve done on MR-1, we’ve always used the small standard driver on the X-axis without any issues (and we take much bigger cuts here than anything we’ve seen customers attempt so far :rofl:). The fact is that the X-axis uses a ball screw with significantly less rotating friction than the Z-axis lead nut. It also, doesn’t need to lift up the 60lb+ spindle assembly that is required by the Z-axis. In addition, the published Max Thrust values for the X-axis on our website spec table (135 lbs) was rated using the smaller driver on the X-axis. The Three MR-1 machines that we have sitting in our prototype shop that we run daily for rework and production all have the standard sized driver on the X-axis.
  • The High Powered Driver add-on option is still available for sale on our website. Users can choose to put these higher powered drivers in X or Y (need 2 drivers) if that is desired. In the not too distant future we are going to release the High Feed Speed Ball Screw upgrade option for MR-1 that increases the machine rapids up to 200 IPM. Having the larger drivers on the X and Y axes (3 total) will be required to run these new ball screws. This add-on feature will be great for folks running softer metals/plastics and doing a lot of 3D surfacing type of operations.
  • Using the High Powered Driver on the Z-axis provides many additional benefits such as better drilling performance and better end mill plunging capabilities.

Hope this helps!


So if I order two more high power drivers you think my hard stop x direction problem will disappear. I already have one on my Z.

hey @Bigdaddy2166 i believe your issue is different from the one that is the subject of this thread. Would you mind starting a separate thread dedicated to your specific issue? A video would be very helpful.

You got it.

I cant wait for the higher power faster option.

cant find the PDF with the swap instructions @langmuir-mike

Go to the main page-Support-MR1 assembly. You will find in there the instruction how to install the Zaxis drive. IS this what you are asking?

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Is there any update on the ball screw upgrade?