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  1. #1
    Hi!

    Iím unsure of what couplings to use. As it seems I will go with alu couplings with a slit in them. Any thoughts about that?
    Iíve noticed that the ball screws are round at the end. Is there any reason that they donít have a flat surface as the motors has?
    Iím thinking that maybe if something goes wrong they will come loose and prevent further damage.

    Thanks, JW

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  2. #2
    No, they are the worst coupling to use. you are better using an Oldham-type coupling like this.

    http://www.fbtmotion.com/html/16.html

    Or better still a disc type coupling like this

    http://www.fbtmotion.com/html/17.html

    Regards the ball screw then just file a small flat onto the shaft, the machined portion is soft enough to file.
    -use common sense, if you lack it, there is no software to help that.

    Email: [email protected]

    Web site: www.jazzcnc.co.uk

  3. #3
    Thanks!

    I guess the coupling is flexible above a certain amount of torque right?
    Last edited by JW1977; 25-04-2021 at 11:54 AM.

  4. #4
    Quote Originally Posted by JW1977 View Post
    Thanks!

    I guess the coupling is flexible above a certain amount of torque right?
    I've snapped 3 of those metal 'flexible' couplings so far.
    I now use the spider type with no problem at all.

  5. The Following User Says Thank You to dazp1976 For This Useful Post:


  6. #5
    Quote Originally Posted by JW1977 View Post
    Thanks!

    I guess the coupling is flexible above a certain amount of torque right?
    It's all to do with parallel and Angular misalignments and to a lesser degree axial growth or misalignment.

    Read this it will explain the different types and Torque ratings etc.
    https://www.thomasnet.com/articles/h...oupling-types/
    -use common sense, if you lack it, there is no software to help that.

    Email: [email protected]

    Web site: www.jazzcnc.co.uk

  7. The Following User Says Thank You to JAZZCNC For This Useful Post:


  8. #6
    *JAZZCNC*

    Do you have any idea or an example of how much runout that can be accepted in a ballscrew?
    Offcourse its hard to answer and its related to length but i was thinking that maybe you have a general idea?
    Im asking because i had some of mine modified in the ends for different reasons. The guy who did it is an experienced machinist used to high precison machines so i guess that in his world my screws are pretty bent. I dont remember exactly but i think that my 900 mm screw where off by 0,4 mm. Im gonna check for myself when i get it back but i think the measure he referred to was when the screw was laying flat and you measure from the flat surface up to nearest point of the screw...

    Cheers

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