Ball Screw dropped it's bearings...

[valentin]

This weekend I attempted to lubricate the thrust bearings per the instructional PDF provided by Axiom Precision. While disassembling the z-axis assembly, I deviated from the instructions to clean the ball-screw. It slipped my attention that I was turning the ball screw past the ball-nut, and I heard the dreaded sound of tiny-steel-balls landing on my spoils board. I immediately stopped, and took a few minutes to gather all the steel balls. I re-inserted them into the ball nut, and finished the rest of the lubrication instructions.

Once reassembled, I manually ran the z-axis up and down without any problem - except for a small "thump" sound that occurs only once in each direction. Now when I run cut files the z-axis stalls inevitably. I assume that I missed some steel balls (which could have easily rolled away). 

I understand this is entirely user-error. Has anyone here made this mistake before? I'm afraid that I might need to buy a whole new ball screw assembly, unless the ball nut can be repaired (filled with appropriate number of steel balls).

I left a voicemail and email with the Axiom team this morning, hoping to get my machine running asap.

[savannahdan]

That's got to be similar to herding squirrels. I keep a couple of long handled magnetics with the heads wrapped with a zip lock bag for picking up metal objects. That's not a guarantee that it will get all of what I drop. Glad you posted so that I can be careful doing this maintenance chore. Good luck and keep us posted on the outcome.

[valentin]

Problem Solved!
I took a closer look at the ball-bearings that I had packed into the ball-nut, and I found one ball that was smaller than the rest! There's a chance that this is by design, but I figured that I mistakenly inserted a rogue ball, which must have been lingering under my machine who-know how long. I removed the runt-ball, but the Z-Axis problem persisted. Finally, I spent an hour trying different alignments mounting the ball-screw and the spindle bracket. There are four screws that hold these together, with about 1-2mm of horizontal play. The key was to assure that the spindle bracket could move freely up-and-down before remounting the spindle and stepper motor. Now my AR-8 Pro is milling 3-D reliefs like a champ again!

[cfhmachado]

I just had this same issue . How do you reinstall the bearings along with the little insert that holds them in place ? Thank you In advance .

[germanguitars]

The good news is that ball screws are not that complicated. I have been using cheap ball screws in a tool I designed to remove and replace rock climbing anchors (  Doodad tool ) - the work is really hard on the ball screws since you get rock dust in them and I'm putting nearly 2000 lbs of linear force on them at times. They typically have just a few parts:

• body
• 2 plastic rings
• several set screws to hold plastic rings in place
• 3 'dot' plastic retainers that are inserted from the inside
• ball bearings

When this ball nut broke, I ordered a replacement for ~$17 off eBay and it worked perfectly. If I broke one on my CNC machine, I might order a higher quality one. 

[cfhmachado]

Thanks for the reply .

Does anyone know what exactly what size ball nut axiom
Cnc require ?