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How to replace anti-backlash nuts?

Posted: Wed Sep 02, 2015 4:29 pm
by salomon
Hello everyone I would like to know what are the steps needed to replace the anti backlash nuts on the Galaxy series CNC machine when they worn out.

I saw in probotix page that they were user replaceable but did not find any indications for this task.

Thank you!

Re: How to replace anti-backlash nuts?

Posted: Thu Sep 03, 2015 9:06 pm
by Keystone Chuck
I had same concern/question when I was buying my Asteroid. I called and spoke with Len and he has said in the entire time he has been at Probtixs he has only sold maybe a dozen backlash nuts. He told me he doesn't understand why he has not sold more that they do not last forever but for what its worth, they are not replacing them as often as you would think. He said it wasn't that difficult that he would talk me through it if the need arised. Mine being only maybe a month old, I don't think thats a need for quite a while....if ever.

Re: How to replace anti-backlash nuts?

Posted: Fri Sep 11, 2015 8:59 am
by salomon
I figured out that to one of my anti backlash nuts worn out and the spring came out, -I dont know if the gramatic is ok-, but that was what happened! So I really need to know how to do that and also where can I buy them cheaper, we are facing several economics problem here in Venezuela, and trust me, those nuts at $50 each represent (now) a very significant ammount :(

best regards

Re: How to replace anti-backlash nuts?

Posted: Thu Oct 01, 2015 4:25 pm
by salomon
Len are you there?????

Re: How to replace anti-backlash nuts?

Posted: Mon Oct 05, 2015 11:32 pm
by probotixmissy
We have two anti-backlash nuts for the Galaxy series machines on this page:

I am not sure where you could get them cheaper but I will check around and post back my findings.

Are you looking for step by step instructions for swapping them out? If so let me know I can put some instructions together.


Re: How to replace anti-backlash nuts?

Posted: Tue Oct 06, 2015 8:31 am
by salomon
Hello again,

Thanks for replying, please tell me what you find!

And yes please add step by step instructions how to do the task.

Best regards

Re: How to replace anti-backlash nuts?

Posted: Mon Oct 19, 2015 11:18 am
by probotixmissy
1. Remove the 3 screws on the AB Nut
2. Loosen the lock collars and the ends of the Y lead screw closest to motor
3. Remove screw from shaft coupler closest to the foot or upgright so screw can be manually turned
4. Thread the rod through about 5" so there is a gap by the motor and the screw sticks out the back
5. Take out the 3 AB nut bolts
6. Use the screw out of the back as leverage to push the AB nut out of the side of the drive block
7. Spin the AB nut up to the gap for removal from the lead screw
8. Put a new AB nut on and twist it down the screw
9. Compress the spring on the AB nut to get it on the screw (at the gap)
10. Spin AB nut back into the side of the drive block
11. Put AB bolts back in
12. Thread rod backwards back towards motor and tighten shaft coupler by reinstalling screws
13. Tighten the lock collar
14. Put all screws back on
15. Do same for X axis
16. For the Z axis, you may need to put a piece of stock on the spoil board to make sure you don't damage it with the screw