I am engaged in a full restoration project of a 150 and while taking the leadscrew and carriage apart I found 122 steel balls (and there was no sign of any balls lost during disassembly). On reassembly, I glued them all in place with grease and it looks like there could be 2-3 more on each nut to completely fill not only the nut but also the "outside reservoir/slot". On a Facebook group, someone wrote that the balls' size should be 4.762mm (which is 3/16") and there should be 67 of them (or one less than full) within each nut. My questions are - is it indeed the "must have" number of balls and will the machine not function correctly if put together with a few balls less than originally designed?
Largest Manufacturing Technology Community on the Web
Stay Connected:
Schaublin 150 Balls in Leadscrew
- Thread starter droren
- Start date
- Replies 16
- Views 607
group 5
Aluminum
- Joined
- Nov 21, 2005
- Location
- Los Angeles
According to the "ball screw" guys, the screw will work fine missing a few balls.
The "ball screw" guys are the best!!!
Degull
Aluminum
- Joined
- Feb 3, 2014
- Location
- Toronto Canada
Give us some pics please!
dgcope
Cast Iron
- Joined
- Feb 7, 2003
- Location
- Athens GA USA
The correct quantity (according to Schaublin drawings) of 3/16" balls is 66 per circuit for a total of 132. Given that precision balls are quite inexpensive, I don't think I would chance running with less than the proper quantity. A partial re-fill is bad form. I think I would replace them all...I think grade 25 balls are commonly used for ballscrews, but even more precise Grade 10 balls are not at all costly. When you buy them in a lot the size consistency is guaranteed.
Thank you,
Already installed it (with 60 balls each, so a 10% decrease), and it was a complete nightmare. There are no directions or explanations anywhere on how it's done. Took me hours and 4-5 attempts. Problem is that the balls will not stay on the internal threads for too long, especially when you tilt and try to install the internal peace or when you try mounting it on the machine. Eventually, I arranged the balls in the internal thread with grease, easily turned the screw inside it, tilt the saddle casing on its side, and ease the whole assembly into the saddle. Then I could (with the help of two friends), assemble the whole thing on the machine.
I'm debating at the moment, after installing quite a few more parts, whether to take it apart again, buy new balls, and repeat the whole process.
Milland
Diamond
- Joined
- Jul 6, 2006
- Location
- Hillsboro, New Hampshire
Just keep in mind that the balls your Bscrew originally used may not be a true nominal size. So if the set you bought goes in "tight", don't muscle through it and try to use it as-is, you may truly damage the screw assembly.
With care, there's ways of measuring the existing balls using stacked gauge blocks and two overhanging blocks to make a "pass through" gauge. This presumes the balls are not significantly worn or out of round, of course...
With care, there's ways of measuring the existing balls using stacked gauge blocks and two overhanging blocks to make a "pass through" gauge. This presumes the balls are not significantly worn or out of round, of course...
Milland
Diamond
- Joined
- Jul 6, 2006
- Location
- Hillsboro, New Hampshire
Not necessarily return to the old, but try to find a bearing ball vendor that will sell small quantities of +/- balls that can be chosen for a proper fit. Also, calipers are only good for gross measurement in this context, you need to be able to resolve to better than 0.001mm in the precision ball world. That, or be patient with trial and error in swapping balls of graded size.
I'm not sure I'm mentally ready for such a process, plus I could not find balls with a higher grade than 100 in my country, so I have to order them from all over the globe, which takes time (especially in such sizes). I have to decide now whether to take it apart again and try the new balls (and if it does not fit I'll go back to the 120 old ones) or to just live it like that and get on with it.
Installed the new balls. 66 in each nut. Broke one of the screws holding the key in the process. Had to turn a new one (it is an odd shape). Cannot feel any significant change in comparison to the old balls (which were only 60 un each nut). It moves quite smoothly. Will optimistically continue rebuilding the rest of the machine - so far so good.
Thanks a lot.
Thanks a lot.
Milland
Diamond
- Joined
- Jul 6, 2006
- Location
- Hillsboro, New Hampshire
Cool, hope the rest of the process goes smoothly.
AlfaGTA
Diamond
- Joined
- Dec 13, 2002
- Location
- Benicia California USA
Interesting photo of the replacement balls.
Seems curious that a package of grade 10 balls is not sold using the actual decimal size......
Have purchased lots of precision balls for repair of ball screws and ball ways for surface grinders etc...and always they were sized and packaged using their actual decimal size.....
Cheers Ross
Seems curious that a package of grade 10 balls is not sold using the actual decimal size......
Have purchased lots of precision balls for repair of ball screws and ball ways for surface grinders etc...and always they were sized and packaged using their actual decimal size.....
Cheers Ross
Got them here:
Simply Bearings Ltd - Ball Bearings, Oil Seals, O-rings, V-Belts, SKF
simplybearings.co.uk
I guess they pack them as you order and stick a label for reference.
