[TXFred]

Is it possible to disassemble the ballnut and reassemble it?

I've got a sticky X axis, and I've cleaned and adjusted every part of the mechanism except the ball nut.

Frederic

[LeeWay]

Typically ball nuts can be disassembled. You might try putting a rag under it and flushing it out with brake or carb cleaner first. If you get some silvery bits out of it, then you may have some split balls or footballs in there. Then you would have to disassemble and replace the balls.

[keen]

Is it possible to disassemble the ballnut and reassemble it?

I've got a sticky X axis, and I've cleaned and adjusted every part of the mechanism except the ball nut.

Frederic

Hi Frederic. One way you can isolate the problem is to remove the X stepper, and turn the ballscrew to see if it is sticky.

If it is sticky it could also be the thrust bearings, see if you can find a way to loosen or by pass the thrust bearings. You may need to remove them so you can turn the ballscrew in its nut isolated from all else.

Keen

[SCzEngrgGroup]

Any ballnut can be disassembled, but they vary greatly in how difficult they are to re-assemble. Often, with the type used in the Tormach mills, you will find it necessary to destroy the plastic "plugs" that act as the ball "returns", and are also used to load the balls into the nut. A typical nut will have anywhere from two to five of these plugs. These plugs are typically molded in-place, and are not made to be removable. However, it is often not difficult to make replacements that can be pressed or glued into place.

That said, if the ballscrew/nut itself is the cause of the loss of smoothness, rather than the bearings, misalignment, etc., it is highly unlikely you'll be able to fix it. If thorough cleaning fails to make it smooth, there is almost certainly something damaged that will not be repairable. If it were me, I'd rig up a means of forcing a solvent, like Mineral Spirits, under pressure, through the nut for a good length of time to ensure it is thoroughly flushed out. I'd then pour heavy oil through it, to ensure it is well lubricated. This is facilitated by removing the plastic "scrapers", which are usually just held in with a couple of tiny set-screws. If that did not restore the smoothness, I'd be looking for a replacement.

Regards,
Ray L.

[keen]

"That said, if the ballscrew/nut itself is the cause of the loss of smoothness, rather than the bearings, misalignment, etc., it is highly unlikely you'll be able to fix it. If thorough cleaning fails to make it smooth, there is almost certainly something damaged that will not be repairable. If it were me, I'd rig up a means of forcing a solvent, like Mineral Spirits, under pressure, through the nut for a good length of time to ensure it is thoroughly flushed out. I'd then pour heavy oil through it, to ensure it is well lubricated. This is facilitated by removing the plastic "scrapers", which are usually just held in with a couple of tiny set-screws. If that did not restore the smoothness, I'd be looking for a replacement."

I have to agree with that, I once spent a lot of time replacing balls and polishing scuffed seats in some noisy spindle bearings - it was a complete waste of time.

keen

[LeeWay]

I have only had good luck redoing the balls in nuts like from Thompson and NSK that have an exposed tube that is designed to come apart and repair. Like Ray mentioned though, the smooth type with molded plugs aren't really designed to be reworked. Considering the effort and frustration I had with nuts designed to be repaired, I would not consider doing one that wasn't.

[bevinp]

TXFred,
When you say "sticky" what do you mean? When using the jogger, does the table not move for a few steps then jumps, or is it something else?
Bevin

[TXFred]

TXFred,
When you say "sticky" what do you mean? When using the jogger, does the table not move for a few steps then jumps, or is it something else?
Bevin

The stepper frequently misses steps or binds up. However, it turned out to be an electronics problem. I had cleverly installed a network card in the computer, and it was interfering with the parallel port's timing. (As all of the warnings said that it would.) Once I removed it, everything ran smoothly.

Before I found the real problem, I followed Ray's advice for cleaning the ballnut, and it did flush out some junk. But the good news is that the mill is running smoothly again, and I don't have to spend hundreds for a new ballscrew/nut assembly.

[mountaindew]

Great news!
I was thinking I seen price for y axis was just under 600$ from tormach, ouch . They also make a x or y thrust bearing adjustment kit that has a nifty handle and shaft to clamp in place of stepper motor. Pretty easy to run the complete axis travel by hand and feel both preload and possibly other problems with ballscrew or ways. Also easy to make one from stuff around shop and it makes checking axis travel pretty simple and a good diagnostic tool to have on hand.

[LeeWay]

I have the large kit for that. It's called a 15L Slant Pro lathe.

[mountaindew]

I have the large kit for that. It's called a 15L Slant Pro lathe.

I mentioned it because I was using the kit that very day to move x,y, around and check adjustment on my mill because I had it apart.
This thread and another on lubrication of ballscrews had me wondering if in fact they were getting lube. Out come tools, mirrors and lights to observe lube in action on each ballscrew.
I don't have a cool camera-scope like others , anyway I sleep better knowing those 600$ screws are lubed.