Y axis won’t move

Just got my Pro assembled and was jogging the machine to the lower right as per assembly instructions. The x axis performs flawlessly, however, the y axis binds upon movement and thus will not move. I can’t reason why this is happening as I can turn the lead screws by hand and the y axis moves. I have examined the lead nuts and they appear ok. I have even put a spot of oil on the lead screws with no avail. If I push back on the white collar on the LH side the y axis moves in the negative y direction but will not move in the positive. Any support for this? Thanks

Are you positive that the motor coupler is not slipping?

Yep, that was the issue; one coupler needed to be torqued a bit more. I guess I took your warning to heart-“Caution: Excessive torque can cause the screws or hex key to strip”. Thanks for the quick and knowledgeable response.

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We should probably take that note out of the instructions then! Glad to hear it’s working now.

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I am having the same issue. The couplers on both sides are tight. it only moves well on lower IPM’s. Tried a bit of oil but that’s not working. Tried loosening and tightening the bearings. it almost seems like one side moves before the other.

To verify the couplings are tight, wrap a piece of tape around the threaded rod to create a flag. This will confirm visually the couplings are not slipping. I was sure mine were tight also, but after doing this test it proved they were not tight enough and the one y axis was slipping on the coupling. Hope this helps.

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tried the flags. no issues there. I shot a video to better show what my issue is. https://youtu.be/0H6JaGqO3Lk

Try loosening the lead nuts from the mounts on both sides and see if that helps. they could have been tightened slightly off center to make it bind.

I found the issue. The coupling was tight but the motor was still slipping when it met adversity on the motor side of the coupling. The hex screw is unfortunately stripped but I have a spare. I switched it out on both sides and we are running smoothly now. Thank you for your help. I would not of noticed if I didn’t check out the lead nut and realized there was a lot of play on the y axis lead screw when the motor was on when there should be no play at all.

I just assembled mine and rand the break in file. The x axis was moving great. My y axis motor is slipping. I retightened it. Ran the file again and same thing. This happened 3-4 times. Is their a better solution for this? Curious as to what people are doing.

I would highly recheck your gantry travel before you et frustrated with the motor couplers…

Pull out you drive shafts…make sure your gantry glides easily in all directions…and I mean it should glide…

then put your drive shafts back in…and tighten the couplers again…

We have seen people with out of square tables and over tightened bearings that cause couplers to slip.

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ok, sounds good. It doesn’t seam like they glide smoothly at all. At last not the Y axis. What a pain!

yup…most likely your bearings are too tight…it should glide real easy

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I had a chance to look at the table today. It appears some bearings move on the upper rail and others do not. Could this be the issue? If so, how do I adjust them? Just to be clear, are they suppose to spin freely or not spin by hand?

not all bearings have to touch…
the trick is to have a smooth gantry without wobble

The Gantry tubes are not machined! So, here is what I found on my Pro. The tubes are nice and straight but not flat. The surface has high and low spots, not real bad but they are there. So what I did was, before I installed the ball screws I moved the guides along the tube and looked for the high spots. I adjusted the bearings in this high spot, marked the area and then moved it again from end to end. When I was sure I had the bearings adjusted so they would glide smoothly I moved to the next one. Not all bearings will touch at the same time. When I adjusted Y axis I made sure that when I moved Y all the way to the front that both carriages were against the stanchion plates and tightened the bolts on the X axis tube. If you do not have enough hole clearance to tighten the bolts and keep the carriages against the stanchion plates your machine may be too far out of square. I installed the ball screws and hooked up the motors and when I moved Y to the back and back to the front I made sure to check that both carriages touched the stanchions. At least within .01". I have had to adjust one time after I ran the machine a few times. After you get your machine running and it has run for a couple of weeks it is a good Idea to check all bolts. I check the couplers at least once a week to make sure all is good. Those couplers can be troublesome… Keep the tubes clean! Put a little light oil on the ball screws from time to time so they do not dry out and do not forget the Z axis if you have THC. It is best that after you have the kinks worked out to put a guard over the Y ball screws for protection. I believe that in one of the installation videos they explain this.


has anyone helped with this issue?

hello…what seems to be the problem as there are several things dealt with in this thread…and to keep your information in one place…I would post issues with your table under the same thread we were working with you on for the whole table…that way we can keep going and help make your machine perfect…by posting around right now you might get different solutions.

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And give poor @toolboy whiplash! That wouldn’t be good for any of us!

Coming soon to a shop near you, the Toolboy bobblehead :laughing: