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Ballscrew rework

I've got an 'Acupath mill' ( Taiwanese import mill vintage 80's) with a trashed X axis ball screw. The move crew took it apart to get it in the room, the results was the little balls all over the inside of the knee. I think I have a way to fix it.

I need to find a stray ball somewhere in the nooks and crannies of the machine so I can order some new balls. McMaster has a huge selection of inch and metric balls, usually run about $.10 each, need perhaps 150 of them so $15 or $20 would cover it. This site shows how a ball screw nut is threaded on a ball screw:

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the arbor was a chunk of aluminum in the proper size, had a suitable groove cut in one end, one should be able to populate the ball screw nut by holding the grooved end up and dropping them in one by one. Once it's full, transfer to a tube with a sharp edge, screw it on to the screw.

Wadda ya think?

Reply to
RoyJ
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Probably do-able, but not a lot of fun. Check carefully as there are most likely two sizes of balls that alternate.

Reply to
Pete C.

Depends on how far away and how much...

Take a look / post on cnczone.com, plenty of home builders there and the occasional unintentional ballscrew disassembly. Should be some good references to ballscrew repacking to be found.

Reply to
Pete C.

Roy, I think you ought to send it off to a ball screw rebuilder and let them refill the ballscrew. They will check it and used the proper sized balls, putting it as good as new..or damned close.

And its not all that expensive

Gunner

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Reply to
Gunner Asch

Not as many references as I would have expected but some good info none the less. Thanks.

The different sized balls worries me a bit. I doubt if I will be able to f> RoyJ wrote:

Reply to
RoyJ

Having the wrong sized balls overall will give you backlash, having them all the same size will give you rapid wear. Think of how a ballscrew works - the balls are rolling along between the two surfaces, the ballscrew and the ball nut. All rolling in the same direction, i.e. the front of one ball and the back of the one in front of it are going in opposing directions, so if they contact they rub and wear. The intermediate undersized balls placed between them contact to two balls and act as an idler, and since they are undersized they do not contact both the ballscrew and nut.

Reply to
Pete C.

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This place has VERY fast turn-around or very good prices on repair. Even the standard turn-around is pretty fast.

I have used them several times...first one was a 1 1/2" dia. 72" long...I dropped it off after work sorta on my way home...next day, they call to tell me it was done...at 11:00am. AND they had their driver going out anyway, he'd drop it off...machine was back online by close of the first shift...total lost time 36 hrs...cost...$500.us

Cheap at twice the price.

Mike

Reply to
The Davenport's

I sure hope you find a few balls. Mic them all, as others mentioned, every other ball is smaller to be a spacer of sorts that doesn't bind.

Wes

Reply to
Wes

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