Excessive slop in x axis

Anyone else noticed the X axis got really sloppy really fast? I have an X50 woodworker and I have around .010" of slop in the x axis bearings. I can rock the gantry left and right a lot without the screw twisting. It’s not really backlash, although the backlash on x isnt great either, its more the bearings are bad already. It’s only been a few months and I get chatter cutting soft epoxy.

I upgraded to the X50 from the X35 recently, but am still working on my set-up (no milling/carving yet). When switching out the stepper (I use different ones on my machine), I found a lot of play as well. I had to very carefully fine tune the amount of tightening I did on the ball screw nut to stop the play I noticed. Part of my set-up will include a quantitative check of accuracy, repeatability, backlash, etc…

I would check to make sure the ball nut is secured to the housing (i.e. screws didn’t loosen up on it), then check for proper tightness in the nut at the end of the screw to ensure proper preload.

Shortly after I setup my machine, I began installing a drag chain. During the testing for length, I was pulling the X axis by the Z carriage and noticed this as well. It was the X axis nut that was not tightened enough. Onefinity created a video on the subject I believe. Tighten until the washer will not spin, then back off until it does, from memory.

I am hoping the folks at onefinity we’ll see this post and add the video on how to correctly tighten the axis nut

From what I have learned, a video may not be needed. The instructions I have read, were the same as @JCNewcomb mentioned. Tighten the nut until the washer will not spin, then back the nut off slightly until the washer barely is able to spin.
This video is informative in that it demonstrates how to safely hold the ball screw while tightening the nut.


Perfect ty
I am nothing less than sure you are right and I thank you for accommodating

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so I started tearing stuff apart, and the linear bearing are toasted. Both the 50mm bearings have about .005 wiggle up and down. That causes the gantry to have almost .010 of just free movement, that cause it to bounce around when cutting. I tested the 35mm bearings on the Y axis and they had less than half a thou on all the ones I tested. I’m feeling kinda bummed out I got the X50 with the crappy bearings, should have just gotten the x35 with the stiffy and had way better rigidity.

Hey Jacob,

now you are talking about up and down. In your first post you mentioned left and right, which would rather be play in the ball nut attachment. If you say up and down now, it should be back and forth too. That would mean, you can twist the gantry, upper part back, lower part towards yourself of what amount?

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Yes, when I said side to side I wasn’t clear with my words. I can push the top left, and the bottom right, in sort of a rocking motion. I put an indicator on the bottom right of the z axis plate and with gentle pushing the bottom and pulling the top it was just under 10 thou of forward and back movement, if I push/pull hard it gets closer to 20. I then took the whole zaxis off to remove any play in that plate and indicated the bottom of the gantry and was again able to pull the top and push the bottom to almost 20 thou when pulling/pushing with a decent amount of force.

I also made the upgrade to the X50, but am not quite ready yet to do the kind of testing you are doing. May I ask, what happens to the indicator when you do not touch the z assembly, but rather push down on your table, and on each of the 4 y axis blocks?

I will try doing similar tests in the coming days. I am also curious as to the manufacturer’s acceptable tolerances for this brand/size of linear bearing.

On my Journeyman Z slider plate bottom left corner I am measuring .0009" deflection with 20lbs of force applied to the right lower corner, I measure no .0002" when I apply 20lbs of force to the upper right corner.

Thanks, thats good to know that other machines don’t have the same movement. On mine there is about .008 movement with less than 5 pounds of pressure, and that jumps way up with more pressure.

I did what you asked, my table had more movement than I thought it would, as it’s 4x4 steel tubing, the mdf may be the next thing I change. It moved about .006. the y axis movement was almost non existent, less than my 1 thou indicator could detect.

Are these tests in the X plane (from side to side), or the Y plane (from front to back)?

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X plane with a dial indicator on the bottom left side of the .250" thick plate bolted to the X gantry.

Thank you. I ask because I am currently troubleshooting excessive play in the Y plane of my X50 Woodworker’s Z assembly/x axis gantry.

To add one thing, I was holding the ball screw in place to ensure it didn’t rotate as well.

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Curious if any of you managed to fix the problem. I definitely have +/-.05mm of play in the balls screws on x and y. Balls screws themselves have zero play but it seems like there is a lot of play in the ballscrew nuts. Very evident when doing climb milling in aluminum.