Ball screw balls came out of the nuts. Can I reinstall them?

Question: I ran my ball nuts past the end of the screw. Is it possible to put the balls back in the nuts?

A coworker started the assembly process for our machine, and he installed the limit switches incorrectly - wrong ones installed in each location. I did not discover this until I was doing the final machine wiring. I realized I could remove a few mechanical parts, slide the gantry to the very end of the round black rails, and access the limit switch screws (@langmuirsystems would be so nice if the Y axis end stops were 2-5mm lower, then this would not be necessary).

Now if I had removed the end screws in the ball screws at the front of the machine, I could have avoided what happened next. I pulled the gantry to the absolute end of the travel, exposing the end stops… and running the ball nuts off the screws. I immediately ran the screws back in to the nuts, but this pushed out a bunch of balls. I saved the balls separately for each motor as grease kept them clumped together. Is it possible to put them back?


I think I read in the instructions be very careful not to move ball nuts off the screws as they will get destroyed and be expensive to replace…doesnt sound good.

Here’s a YouTube video putting balls in an assembly like that.

It isn’t a langmuir specific video but it is a ball screw specific video.


Perfect that looks pretty doable. Not the disaster I was worried it will be. (Would have been worse if I hadn’t already greased them, as balls could have fallen on the floor). Thank you!

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Please post your attempt! I imagine this might happen again to someone.

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Good call will do.

I stupidly did that once!
I was working on my Z-axis in haste and did not think it through before-hand. There were little balls all over the place. I got most of them back I think, but can’t be certain. Fast-forwarding, I can tell you, it’s a ROYAL PAIN IN THE ASS to get them back in!
I eventually bought a new linear unit since I did not trust my re-assembled unit. :grimacing: :beers:


Another confession:
I once decided to take apart a stepper motor. Immediately I pulled out the rotor from the stator, that “magic magnetism genie” vanished into thin air …pooof! :crazy_face: :rofl: :rofl: :rofl: :rofl:


Okay I had complete success! I replaced all balls and everything moves smoothly and tight like it should. I got the machine fully assembled and have done the full motion break in and some test cuts and everything looks great.

All you have to do is strip down this end of the ball nut, including removing the recirculator, insert all the balls in to the groove, reinsert the recirculator, secure everything back on the nut and you are good to go! Note that the recirculator has a tab that fits in to the screw so you have to have the screw down in the nut just below the recirculator to get it in or out. By the way you must remove the recirculator because it blocks the balls going in to the screw path. That was one difference from the above YouTube video.

Some pics:

(Work over a box because you will drop some!)


Well done! :beers:

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You will give others hope in the future…nice job!

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I’m finally assembling my XR 4x8 and somehow the ballnut came off the ballscrew and I dont know how many ball bearings are required to pack into the nut as you load the screw, The screw is the same one shown above. I measured the Ball bearings, and they are 1mm, also should you fill the return with ballbearings when loading in the bearings?

Correction, the BB are 2.5mm not 1 mm,