What's new
What's new

Ballscrew rebuilders in Texas. Any experiences?

The topic of "rebuilding" ballscrews interests me. In >40 years of CNC experience, I have never really been satisfied with the performance of a rebuilt ballscrew despite trying several different rebuilders. At the very best they have not been as smooth and quiet as a new screw (maybe I am being too picky?). At the very worst, the rebuilders ground too much from the screw which left the remaining case-hardened thickness too thin causing rapid total failure.

Because of all the repeated issues with "rebuilt" ballscrews, I quit trying them about 15 years ago and only used new replacements since.
 
Vancbiker, have you ever seen a "simple" reballing (no grinding of screw or nut) work satisfactorily?

Not to my satisfaction. Always noisy and rough rotation compared to a new assembly. I have only had re-balling done on single nut type ballscrews where the goal was to reduce the clearance so slightly larger balls were used. Introducing pre load back into a somewhat worn screw and more worn nut is almost certainly the cause of that.

Performance wise, most re-balled screws position OK once pitch comps were determined by laser interferometer and set in the control. Biggest objection was the noisy travel. Service life may have been less, but that was not able to be accurately tracked.
 
I had the Z axis on a Monarch Metalist re-balled some 20 years ago. Guy came out to the shop and was done in about 3 hours. I was satisfied with it.

This ballscrew is on my cheesy-ass Taiwanese flatbed lathe that seems to be built following the formula described by G-coder05 about crappy Chinese machines.
Shinri cnc lathe, any input? Any good?
 
Need to get a ballscrew repaired. I think it just needs to be re-balled. Any one have experience/recommendations for companies in Texas?

For big machines we have had great luck with sending them out, HES, big mories and mazaks and a few others. for little machines Ie standard mills like fadals haas yci,etc etc and others in my opinion not cost justifiable. we used to send out a ton of acroloc balls screws back in the 80's and early 90s for rebuilt. then we found you can get new ones and just modify he ends cheaper we we started doing that.

I know there is one place in txa to stay away from, but I believe he went out of business about 5 years ago(cant remember the name) few places in texas were good most we sent to someplace in the upper midwest.

we sent them for regrind never just new balls as the screws usually have high and low spots and new balls just make them sloppy and tight and noisy.


If you can wait till next week I can get you some names as my neighbor is out of town till next week. pm me your email addy.
 
Do you have any sense of the condition of the ball path? Is the screw accessible or is it buried? And is it making noise over the entire travel, or just in spots?

X axis screw. Easily removed. Noisy and rough full length. Noticed some pitting in several places. Highly unlikely to find an off-the-shelf replacement.
 
Is getting a new screw and nut then modifying the ends to suit an option you would entertain? I would think it would be much cheaper than a rebuild and probably much better working.
 
Is getting a new screw and nut then modifying the ends to suit an option you would entertain? I would think it would be much cheaper than a rebuild and probably much better working.

I would entertain that if I could find something to work with. The nut is stamped CBC(as a logo) 21616-1-2. Google hasn't found anything relevant.
 
I have a ton of ballscrews here, mostly larger but some smaller. If you get a moment, get some rough numbers off the existing one (major diameter, pitch, length, nut geometry, etc.) and I'll see if anything I have could work. Even different pitch shouldn't matter if you have access to the parameters in the control.
 
Top shop in Michigan, I have known since the 60S

Custom Ball Screw Manufacturing, Precision Machining, Ball Screw Repair - Sterling Heights, MI

You should build a wood box even if sending just down the block, so this outfit is only UPS away.

I sent these guys a ballscrew from my Mazak for rebuild, IIRC based on recommendations here on PM. Unsuprisingly, it was too far gone for rebuilding (very abused machine I resurrected) but they were able to fabricate a new one for significantly less than what Mazak wanted. I had a couple issues with the finished product- the male threads were wrong on the end where a retaining nut screws on and the shaft where the servo coupling attaches was oversize. Unfortunately only discovered this through the course of two expensive service visits to reinstall the screw. They fixed the thread issue but I didn't discover the oversize shaft until later so I ended up modifying the coupling myself. Since then I have had no additional issues with the ballscrew and it performs as expected, but between the extra days I had a tech out here and all the time lost going back and forth I would have been better off time-wise and expense-wise if I had just bought a new Mazak ballscrew from the start. I said as much to the TC customer service guy who followed up with me after the rework, he was very apologetic and promised to look into it, but 2 years later it seems to have been forgotten.

TL;DR: Had ballscrew made by Threadcraft after reading recommendations here, new screw was cheaper than OEM but had minor issues that caused a lot of additional hassle, downtime and expense.
 
Ill add myself to the list of "Buy a new screw". Had multiple vender issues in Texas from lost screw, to WAY late on delivery. The screw that I had the best luck with still wore quickly. If this is a machine that can pay you back with the time saved than go new. Skip the headaches
 
I'm thinking a lot of the cost of a new screw is machining the ends, which we as machinists ought to be able to do. Take a look here to see if they have your screw stock and nut, I would think you could get the screw cut to your length with a nut for a reasonable price. I got my rails and blocks from them for a drill/tap machine I have, made to order for half the price of anywhere else and no issues with the quality. Their about 5 years old now and making parts right now. I really need to replace the X and Y axis screws on the same mill but haven't taken the time to see what they want for the screws and nuts. My unmentionable lathe has just over a 32mm bore so I could do the end machining on it. Their not pre-tensioned so the distance between the end machining isn't critical, just has to be close. From my experience reballing screws these things are real finicky and their aint no substitute for new, not close.
 








 
Back
Top