I think I messed this up - ball nut?

My Y- axis was stopping, so I started taking stuff apart. I replaced all the basic bearing earlier this year. It was grinding a lot, so I took this thing of and some ball bearings fell out.

Is it right that I need to replace the long shaft with a new bearing?

This is a 3925. I can almost get three guitar bodies side by side. But not quite. I'm thinking I should consider rebuilding out to 45 or so. It looks like I'd need two longer tracks. I'm scoping it for other stuff.

Is there a good place for parts like this?

Chris

That's ballscrew and ballscrew nut..

Thanks.

So both get replaced or can I just buy a ballscrew nut?

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Originally Posted by ger21

That's ballscrew and ballscrew nut..

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If the screw is not damaged, repacking the ball nut is not difficult, but it does take some patience. New bearing balls are available from any bearing supply. But you have to make sure you get them in the correct size.

You can also buy a new ball nut, an example: SFU1605-3 ballscrew nut 16 mm ball screw single nut

Perfect Thanks.

Quote:

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Originally Posted by Jim Dawson

If the screw is not damaged, repacking the ball nut is not difficult, but it does take some patience. New bearing balls are available from any bearing supply. But you have to make sure you get them in the correct size.

You can also buy a new ball nut, an example: SFU1605-3 ballscrew nut 16 mm ball screw single nut

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@ OP rebuilding it is a lot more cheaper than replacing the whole thing, that thing cost a lot of $$$ on my opinion.

Step 1: Take out all the ball bearings and wash the hole thing with kerosene or gasoline or whatever solvent you got in your area, use a toothbrush to scrape all the gunk inside the screw nut, blow compressed air to flush everything out leaving a clean, shiny, uncontaminated and oil free ball screw nut.

Step 2: Divide the ball bearings into 4 groups, also clean it thoroughly just like the ball screw nut, after that apply multipurpose grease inside the ball screw nut, then slowly put back the ball bearing inside the ball screw piece by piece using a magnetic screw driver, stick it on the grease you applied until all of them installed back, screw back the screw shaft and it`s done, wash it with kerosene again to take out the thick grease you put in, and use a cooking oil (thin oil) to lubricate it, thick oil tends to attract more dust particles and get your ball screw contaminated in a short period of time, at least the cooking oil is not that sticky, you can blow clean it using a compressed air (120 PSI)

http://www.cnczone.com/forums/attach...d=381634&stc=1

This is how you test the ball screw make sure it`s not sticking, the nut should fall free flow down the shaft backlash-free

https://www.youtube.com/watch?v=ckD0Fv_Uf18

The rebuild seems like it is more skill than I have. It is more patience too. Plus I have no idea where to buy the new bearings, or how to figure out the size.

So I ordered the new one recommended. I'm pretty sure it is too small. Here are the two. The one on the right is the old one.

I see the gray ones one amazon, but they all have the whole thing.

Does anyone know that part number I need?

Attachment 383076

Without knowing what the specs (lead, pitch, diameter) are on your ball screw, it would be impossible to supply a part number. The EXAMPLE that I linked to above was not intended to be the correct nut, but rather to give you an idea of what you could buy and a possible vendor. On the other hand the two nuts in your image look pretty close from the outside. Are there any numbers on your old nut?

In the gray spot one says 16 and one says 5. So I'd guess 16mm. The new one said T6, so I tried t5, but didn't see much.

Do these numbers tell enough If not, how do I measure what I need too. This is a K2 machine.

Quote:

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Originally Posted by Jim Dawson

Without knowing what the specs (lead, pitch, diameter) are on your ball screw, it would be impossible to supply a part number. The EXAMPLE that I linked to above was not intended to be the correct nut, but rather to give you an idea of what you could buy and a possible vendor. On the other hand the two nuts in your image look pretty close from the outside. Are there any numbers on your old nut?

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Tool Supply on eBay has a very good selection of balls, take your time and measure one of the old ones you still have.


Great deals from ToolSupply | eBay Stores

See attached video's for tutorials:

https://www.youtube.com/watch?v=8a14YbmUEHE

https://www.youtube.com/watch?v=GXdt5M8ZeoE

Jeff...

That could be 16mm x 5mm per turn. If that is the case, a SFU1605-3 nut might work fine. The ball screw in your first picture looks like a single start screw, so you should be good there.

That is the one I ordered from the link that didn't fit.

Quote:

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Originally Posted by Jim Dawson

That could be 16mm x 5mm per turn. If that is the case, a SFU1605-3 nut might work fine. The ball screw in your first picture looks like a single start screw, so you should be good there.

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It could be that all 1605 ball screws/nuts are not created equal. You might try removing the plastic shield in the end of the nut and try again, it may be tight. Use extreme caution so you don't lose the balls out of the nut. The only thing that is holding the balls in is the plastic shipping tube. You normally screw the screw into the nut and push that tube out with the screw.

The 3 I measured are the same out to 4 places. So I ordered some to try.

Quote:

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Originally Posted by jalessi

Tool Supply on eBay has a very good selection of balls, take your time and measure one of the old ones you still have.

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I tried that. I already spilled them. I figured that would happen. One Amazon review had that issue.

Now that the plastic is off, I'll see if it fits. I don't think so though.

Quote:

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Originally Posted by Jim Dawson

It could be that all 1605 ball screws/nuts are not created equal. You might try removing the plastic shield in the end of the nut and try again, it may be tight. Use extreme caution so you don't lose the balls out of the nut. The only thing that is holding the balls in is the plastic shipping tube. You normally screw the screw into the nut and push that tube out with the screw.

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Chris,

Are you sure its a 16mm and not a 20mm screw? 16mm is very small for the size router you have.

Jeff...

Chinese ballnut dimension chart:

It measures 16. I'll try repacking once I get the package.

Quote:

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Originally Posted by jalessi

Chris,

Are you sure its a 16mm and not a 20mm screw? 16mm is very small for the size router you have.

Jeff...

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I watched the video on the repacking and tried it. It look me a while. I could not really tell the place he said to avoid, so it did lock up. I put it in a vice to twist it, and a LOT of bearings popped out each side. I'd say half or more. It did twist OK after that. When I reassembled, I found out I had it on the wrong side of the plate. So I did a re-do. I can take it apart or reassemble in about 10 minutes now.

I'm usually better the second time around, but not much on this repacking. I put it all back together again. This is on my y-axis. It makes some noise, but moves ok, still a bit jerky.

I did some tests - trying to finish a piece, and it still stopped. That was my original issue. The dust collector put a bit of drag on the system, so I extended that hose. I took apart teh controller and tightened up all the screws and blew out the dust. At one point I had a bad ground. That thing is pretty low quality.

Then I greased it all up - super overkill. Some of my grease fittings broke over the years. So I was just putting grease on the rails. I can't seem to find replacements. I was scolded by the guy selling those on ebay one - that I bought the wrong ones. I can read, I just don't know the lingo. Agh. So I found today that I can take one grease fitting off, then leave it in the gun and hold it up to the hole and that works. I was out of white grease, so I have this back stuff all over the place. Messy. Agh. Then I turned down the acceleration on the motors. The Z seems to have a nice dampened feel, but the x and y are still pretty abrupt.

With all that, it seems to work. I'm on my second run of two guitar bodies. Here is a picture of what I'm up to. I'd like to get that ball nut in better shape, but I need to get a few guitar orders done.

Attachment 383446

Chris,

Chai at linearmotionbearings2008 will make a replacement ballscrew's to your exact dimensions if you provide accurate drawings and he is very reasonably priced.

linearmotionbearings | eBay Stores

Taking the time to spotlessly clean the linear rails and bearings might also be a good idea.

The linear bearings should have part numbers so that you can identify the manufacturer of said parts and order the correct grease fittings.

If you don't have time to take care of the machine and do preventive maintenance you might be chasing gremlins for the foreseeable future.

Jeff...