Lost my balls!!!

[danielbriggs]

Bugger... :confused:

I thought it prudent to take off the stepper motor and slide the ball screw up on my X-axis from my Boxford 160 lathe I'm working on (build thread to follow when I find time) so I could accurately measure the pitch of the screw to calculate the settings for Mach3 motor pulses.

BIG MISTAKE

It appears that all the balls from the ball screw mounting pillow block have fallen out the bottom. I still have them all in the swarf tray; but that's not the point!!!

I've tried to remove the pillow block, but it seems I'll have to remove the whole X/Z slides to remove it :cry:

Does anyone have ANY ideas as to how to pererably fix or go about replacing the ball screw retainer...? :cry:

Got the biggest sinking feeling and almost shat myself when I realised the bits falling out the base of the slide wasn't old swarf. :surprised:

Ta,
Dan

[Robin Hewitt]

Hard to visualise, a picture would save a thousand words.

If the nut doesn't have a screw fixing on the side you will need pointy tweezers. Stand the screw vertically so you can fight them in from the end while advancing the nut one ball at a time.

[danielbriggs]

I can get some pics tonight.
Thanks for that pointer, I'll give it a try.
Looks like it's gonna be a long evening... :cry:

[Robin Hewitt]

It can be easier to refit the balls if you have the original retainer, the rod cut to just below the nut internal radius. Slightly fiddlier to get it started though. If you make a retainer ensure you bore it so it fits over any reduction on the screw end or they will all drop out again.

[i2i]

correct me if i'm wrong, you're saying the balls have fallen out of one of the bearings at the pulley end of the ballscrew assembly. If so just replace the bearing, they're quite cheap, and may have needed to be replaced anyway. If it's the ballnut balls that have fallen out then that's a different story.:cry:

[danielbriggs]

I'd be over the moon (relatively) if it were in fact the pulley end bearings, but no... it's the ball bearings from the ball screw nut (mounted towards the other end of the pulley in the pillow block) :cry:

There didn't appear to be any plates to hold the balls in; I stupidly wound the ballscrew a little too far out of the nut, then the sound of a "pitter-patter" of balls :cry::cry::cry:

[Robin Hewitt]

There are no 'plates' to hold the balls in, just little diverters that steer them out screw of the and into the recirculation channel.

[Ross77]

Its not to bad a job, I rebuilt one by trial and error and it works fine, I took off the recirculation tube, held the nut on the centre of the the screw, as best I could, and then feed the balls back down the pick up shaft, I did it from one side and used plenty of oil so I could keep pushing them (and rotating the screw) until they appeared at the other side, (That way there are no gaps). Refit the recirulation tube job done...

I tryed other ways but its easy to jam the whole thing up so take your time :o)

[danielbriggs]

Cheers guys; will give it a go when I get home tonight.
i2i, you have a Boxford 160 right? Any pointers to getting the X-axis off easily? I tried last night, but to no avail...

Ta,
Dan

[i2i]

it's going on the bench tomorrow so i'll have a look for you. On the larger machines all you do is take off the motor, unbolt the pulley block, then unbolt the ballscrew block and the whole lot comes out together. Remember to lock off the slide, or it will end up at the bottom of the lathe.