531,920 active members*
2,936 visitors online*
Register for free
Login
IndustryArena Forum > Mechanical Engineering > Linear and Rotary Motion > Some ideas to Back to back double ball nut (no flange type) for my lathe.. possible?
Results 1 to 9 of 9
  1. #1
    Registered
    Join Date
    Mar 2016
    Posts
    61

    Some ideas to Back to back double ball nut (no flange type) for my lathe.. possible?

    Hi!

    I'm converting my mini lathe to a bigger (but still small - 10mm diameter) ballscrew lead screw.

    I want to have a double nut back to back configuration for reducing backlash. I've searched a lot for examples and with the standard flange nut, I can screw one ballnut to the nut block, and the other one would be "floating" fixed only by screws on the fixed nut-block assembly, and by means of springs or tightening these screws a preload would be achieved to reduce backlash.

    something like this in the first picture:



    But as my mini lathe has space constraints, I need to use a flange-less type of ballnut, like this one on the second picture:




    So, I thought about creating a balnut block where I could screw one nut on one side, and the other one on the other side, but then, how would I be able to make them a little apart or a little bit closer to decrease backlash?

    I thought then about using a belleville washer on one side to act as preload, or spring to make both nuts apart, so backlash would be reduced.

    These ideas are drawn below:



    My space constraints are tough. I can't mill the nut block to a higher diameter then the outer diameter of the ballnut external case.

    In my case I plan to use a 1002 ballnut/screw. It has an external diameter of 19.5mm, and I have 21 mm of height under the lathe's bed only.

    Anyone has any ideas if this would work? If not, does enyone has a better idea to couple two flangeless ball nuts in my space constraints?

    Thanks for reading!

  2. #2
    Community Moderator Jim Dawson's Avatar
    Join Date
    Dec 2013
    Posts
    4549

    Re: Some ideas to Back to back double ball nut (no flange type) for my lathe.. possib

    Yes it works. I have done that. Just used set screws against the nut housing, no springs.
    Jim Dawson
    Sandy, Oregon, USA

  3. #3
    Registered
    Join Date
    Mar 2016
    Posts
    61

    Re: Some ideas to Back to back double ball nut (no flange type) for my lathe.. possib

    Quote Originally Posted by Jim Dawson View Post
    Yes it works. I have done that. Just used set screws against the nut housing, no springs.

    Thanks Jim!

    But I'm having a hard time to ..visualize that in practice in my case......

    As the nut housing will be the same diameter (or just 1mm bigger than) of the outer diameter of the nut, where could I put those set screws and how would I adjust them? I have more space laterally than vertically. Laterally I could make a housing a little bit larger.. maybe 2 or 3mm bigger in each side...

    Regards, Rodrigo

  4. #4
    Community Moderator Jim Dawson's Avatar
    Join Date
    Dec 2013
    Posts
    4549

    Re: Some ideas to Back to back double ball nut (no flange type) for my lathe.. possib

    One of my machines had nuts like you show in your last picture. One nut was screwed tight into the nut housing, the other was screwed in and fixed in position with 2 set screws on the sides. You could also just use shims that fit over the threads on the nut to get the correct spacing.

    Sorry I don't have any pictures.
    Jim Dawson
    Sandy, Oregon, USA

  5. #5
    Registered
    Join Date
    Mar 2016
    Posts
    61

    Re: Some ideas to Back to back double ball nut (no flange type) for my lathe.. possib

    Quote Originally Posted by Jim Dawson View Post
    One of my machines had nuts like you show in your last picture. One nut was screwed tight into the nut housing, the other was screwed in and fixed in position with 2 set screws on the sides. You could also just use shims that fit over the threads on the nut to get the correct spacing.

    Sorry I don't have any pictures.
    Ok, thanks Jim!

    What do you think about this new design? Two long (20mm) M2.5mm setscrews that I can adjust from both sides of the fixed nut that push the other nut on the other side.

    Would it be a good set-up?

    Would there be any risk of this other nut with time and use and friction..... unscrew from the housing??

    Thanks for your help!


  6. #6
    Community Moderator Jim Dawson's Avatar
    Join Date
    Dec 2013
    Posts
    4549

    Re: Some ideas to Back to back double ball nut (no flange type) for my lathe.. possib

    An interesting idea, and I think it would work fine. The set screws lock the adjustable nut, so I think there is no problem.

    Maybe some blue loctite on the threads of the nuts would be helpful.
    Jim Dawson
    Sandy, Oregon, USA

  7. #7
    Registered
    Join Date
    Mar 2016
    Posts
    61

    Re: Some ideas to Back to back double ball nut (no flange type) for my lathe.. possib

    Hi Jim!

    I've been thinking.. the set screws design would prevent the nut from .. screwing in the screw, but only the glue would prevent it from screwing out, right?

    What do you think of this other design option? A spacer to a determined thickness and then screws to lock the nut from it's ending. So the spacer wouldn't let the nut screw in, and the screws (with a little flange) wouldn't let the nut screw out.

    Check in the picture, what do you think?

    Or it's too much for it, and just the set screws would be good enough? I'm afraid that, if I use only the set-screws design, and if I glue also the adjustable one, and adjust it wrongly by mistake, it would be a pain to remove it to readjust it...


  8. #8
    Community Moderator Jim Dawson's Avatar
    Join Date
    Dec 2013
    Posts
    4549

    Re: Some ideas to Back to back double ball nut (no flange type) for my lathe.. possib

    I think either way would work. I also think the spacer is not required. Once the set screws are tightened, just the friction on the nut threads will prevent the nut from coming loose.
    Jim Dawson
    Sandy, Oregon, USA

  9. #9
    Registered
    Join Date
    Jun 2013
    Posts
    175

    Re: Some ideas to Back to back double ball nut (no flange type) for my lathe.. possib

    I've just built this for a double nut setup. The rear flange is able to float 15mm longitudinally so I can set the two nuts up on the same plane. Not sure if this kind of thing will work. The slots are 15mm my own pitch is 10mm so should be ok.

    Sent from my SM-N970F using Tapatalk

Similar Threads

  1. add back gears to a lathe
    By pikolo in forum Uncategorised MetalWorking Machines
    Replies: 0
    Last Post: 01-25-2019, 07:45 PM
  2. laser cutting aluminum and stainless back to back
    By foreverdriven in forum General Laser Engraving / Cutting Machine Discussion
    Replies: 3
    Last Post: 03-11-2015, 05:36 AM
  3. Dimension of switch cavity for back control guitar type
    By awe_indo in forum Musical Instrument Design and Construction
    Replies: 13
    Last Post: 12-15-2010, 02:39 PM
  4. z- overun, it will not come back, any ideas?
    By bcdnm in forum General CNC (Mill / Lathe) Control Software (NC)
    Replies: 1
    Last Post: 07-25-2006, 08:41 PM
  5. Old Lathe Back Gear
    By loves80z in forum Mini Lathe
    Replies: 3
    Last Post: 03-20-2006, 11:40 PM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •