1. #1
    Hi

    Doesn't anyone know the spec of the vall screw on the z axis? The bushing on mine has broke the nylon washer had fell and some mini bearings have fell out.

    See pic

    Sent from my SM-N910F using Tapatalk

  2. #2
    Hiya,

    The best thing to do is strip it all down and clean it up, once you've collected all your balls, count them and measure their size, once you know this you can look at replacement balls for/if any are missing.

    I can't remember for sure what screws are used on these machines but I'd bet they are just 1605 ballscrews, again you can measure the screw diameter to confirm this and once we know all this week can advise on what's what.

  3. #3
    Quote Originally Posted by Lee Roberts View Post
    Hiya,

    The best thing to do is strip it all down and clean it up, once you've collected all your balls, count them and measure their size, once you know this you can look at replacement balls for/if any are missing.

    I can't remember for sure what screws are used on these machines but I'd bet they are just 1605 ballscrews, again you can measure the screw diameter to confirm this and once we know all this week can advise on what's what.
    thank you for your response. The ball bearing have come out of the bushing so im looking at replacing that but i dont know the spec of the ball screw.

  4. #4
    If it is a standard ballscrew I can't see how a ball bearing could escape unless the plastic return guide has broken. Wonder if the balls have jammed inside and pushed it out.

    If you can do as Lee suggests and remove the ballscrew it will help identify it.
    When laid out in the bench measure the diameter of the screw and then measure the pitch (distance between peaks or troughs). Also measure the diameter of the ball bearings (micrometer ideally) and take a picture of everything including the ball nut.

    From the picture you have taken it does not look like the usual Chinese ballnut
    Building a CNC machine to make a better one since 2010 . . .
    MK1 (1st photo), MK2, MK3, MK4

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  6. #5
    Quote Originally Posted by routercnc View Post
    If it is a standard ballscrew I can't see how a ball bearing could escape unless the plastic return guide has broken. Wonder if the balls have jammed inside and pushed it out.

    If you can do as Lee suggests and remove the ballscrew it will help identify it.
    When laid out in the bench measure the diameter of the screw and then measure the pitch (distance between peaks or troughs). Also measure the diameter of the ball bearings (micrometer ideally) and take a picture of everything including the ball nut.

    From the picture you have taken it does not look like the usual Chinese ballnut
    Hi

    I have stripped it down. The nylon washer seen in my first pic was at the bottom of the ball screw and not in the correct position and the ball bearings are from the ball nut.

    I think I need to find a replacement nut.

    Sent from my SM-N910F using Tapatalk

  7. #6
    Ok that's better. The first picture was of the supported bearing end not the nut - now we can see the ballnut it is a standard Chinese type.

    Ballscrew is most likely 12mm and the pitch looks like you have measured between a peak and a trough. Needs to be between 2 peaks OR 2 troughs so it is most likely 5mm. So you have a 1205 ballscrew and nut.

    You can try to buy just a new nut but they come as a matched pair with the ballscrew and the ball bearings are sized to be a good fit. That means another random nut may be too tight or too loose on your ballscrew. Unless you have a tuning set of ball bearings your best bet is to strip the nut down, clean it, grease it and reassemble with missing ball bearing in. Chances are it was clogged up inside and jammed the return channel. Have you ever greased the nut?

    When you remove the nut watch out for the remaining balls which will fall out. You will also need a guide tube to sit over the floating end of the ballscrew to guide the nut off and back on again. Once inside the nut look for damage to the plastic returns.

    The are videos on YouTube about repacking ballnuts
    Building a CNC machine to make a better one since 2010 . . .
    MK1 (1st photo), MK2, MK3, MK4

  8. The Following User Says Thank You to routercnc For This Useful Post:


  9. #7
    Quote Originally Posted by routercnc View Post
    Ok that's better. The first picture was of the supported bearing end not the nut - now we can see the ballnut it is a standard Chinese type.

    Ballscrew is most likely 12mm and the pitch looks like you have measured between a peak and a trough. Needs to be between 2 peaks OR 2 troughs so it is most likely 5mm. So you have a 1205 ballscrew and nut.

    You can try to buy just a new nut but they come as a matched pair with the ballscrew and the ball bearings are sized to be a good fit. That means another random nut may be too tight or too loose on your ballscrew. Unless you have a tuning set of ball bearings your best bet is to strip the nut down, clean it, grease it and reassemble with missing ball bearing in. Chances are it was clogged up inside and jammed the return channel. Have you ever greased the nut?

    When you remove the nut watch out for the remaining balls which will fall out. You will also need a guide tube to sit over the floating end of the ballscrew to guide the nut off and back on again. Once inside the nut look for damage to the plastic returns.

    The are videos on YouTube about repacking ballnuts
    Thank you. I'll look into that. I didn't realise they can be repacked. I may buy a new one as a spare.

    Sent from my SM-N910F using Tapatalk

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