[Bearhawk LSA]

Hello All,

I tore down a previously converted machine I bought to clean it up and ended up replacing one ball screw nut on the Y axis. Screw is a 16mm x5mm lead. When installing the nut things did not go well and a few balls were displaced. I looked online and found a few videos on how to reball a nut. I decided to just remove it completely and then reinstall all the balls. that went well but the leadnut is crazy sloppy. I ended up adding a few more balls form the replacement to get to 17 in each track and its still loose. I checked the Ball diameter and both the new ball nut and old have .124" diameter balls. I only have calipers, but they are good ones and both sets of balls measure the same. This seems odd and I wonder if I did anything wrong. The balls must be in the correct tracks otherwise it would lock up after a few turns. The orange ball returns seem sloppy too, I can pinch them and get the screw tighter, but the whole thing sounds like a skateboard bearing form the 70's. Also as I pinch each one, I can feel the balls going through and one of them feels very lumpy as if something is wrong in that track Does .124" size balls seem right base don others who have replaced balls before. I am thinking i should order new larger ones from McMaster but unsure just what to buy. I am open to any help or suggestions.

Best regards,

Marc

[lcvette]

Hello All,

I tore down a previously converted machine I bought to clean it up and ended up replacing one ball screw nut on the Y axis. Screw is a 16mm x5mm lead. When installing the nut things did not go well and a few balls were displaced. I looked online and found a few videos on how to reball a nut. I decided to just remove it completely and then reinstall all the balls. that went well but the leadnut is crazy sloppy. I ended up adding a few more balls form the replacement to get to 17 in each track and its still loose. I checked the Ball diameter and both the new ball nut and old have .124" diameter balls. I only have calipers, but they are good ones and both sets of balls measure the same. This seems odd and I wonder if I did anything wrong. The balls must be in the correct tracks otherwise it would lock up after a few turns. The orange ball returns seem sloppy too, I can pinch them and get the screw tighter, but the whole thing sounds like a skateboard bearing form the 70's. Also as I pinch each one, I can feel the balls going through and one of them feels very lumpy as if something is wrong in that track Does .124" size balls seem right base don others who have replaced balls before. I am thinking i should order new larger ones from McMaster but unsure just what to buy. I am open to any help or suggestions.

Best regards,

Marc

Calipers are not OK for these measurements, most balls are measured down to half a tenth. You need to get yourself a decent micrometer to do the measuring.

I just repacked some and I measured the balls and ordered what I thought was a larger ball diameter, turns out I was measuring wrong according to the ball supplier. You have to be very delicate. I was using the ratcheting knob and was told that's enough to deform the balls and give false readings. Most screws use a "0.125" ball but I have a few screws here that range from .12460" and others in the same set that use .12550". So you will need to measure with a real micrometer and determine what size you have and then buy a few packs of 100 larger to test fit. Remember to measure lightly or you may buy the same size balls like I did

Also with a micrometer, I found I could separate the balls in to matched sets and it made a big difference in how smooth the screws turned.

I know ArizonaVideo repairs alot of ballnuts for improved backlash, perhaps he has some insight or advice to add. Or possibly a source for balls?

Chris

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[arizonavideo]

Do a backlash test for all the axes . I bet each one will have a good amount. It does help to remove the seals to get a good reading if it is new.

I repack them all the time and you cant really measure and guess. A really good fit often depends on a vary vary small difference in size like from .12490" for a good fit to .1293" for too tight of a fit. You don't know the exact fit until you pack the balls.

For not too much I can re pack yours.

Send me a PM.

Thanks
Dave

[lcvette]

Do a backlash test for all the axes . I bet each one will have a good amount. It does help to remove the seals to get a good reading if it is new.

I repack them all the time and you cant really measure and guess. A really good fit often depends on a vary vary small difference in size like from .12490" for a good fit to .1293" for too tight of a fit. You don't know the exact fit until you pack the balls.

For not too much I can re pack yours.

Send me a PM.

Thanks
Dave

@Arizonavideo

Where do you order your balls from? I bought my last batch from tool supply on eBay, but he doesn't have the sizes I want to try now and I'm having trouble finding a place that offers ball sizes in tenths. Any help appreciated!

Chris

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[arizonavideo]

That's the problem.

Ball-tec has all the sizes but charge about $30 per ball + shipping. So if you guess wrong you get to buy more.

Bal-tec - Bearing Steel for Steel Balls

[lcvette]

Wow.. that's not cheap.... Good grief.

I have a decent reference.. the 0.1255" balls were notchy when I tried them in the 0.1248" ballnut. I figure somewhere in between would be the sweet spot between tight and a good close fit, bit I'm not sure I'm wanting to spend $30 per set to experiment. I may see how these do before pulling the trigger or possibly seeing if I can get a few different sizes from one of the Chinese ballnut suppliers to test out.

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[arizonavideo]

24 cents to 30 cents per ball not $30