How many balls in nut?

[phantomcow2]

Is there a standard number of balls in a 5/8-.2 ballnut? I ask because I have just reloaded a regular ballnut after losing the balls. It worked well, but I have one more to do, and want to make sure I have the amount of balls I should.

[Adobe Machine]

1) Determine size; .125 ? .150 ? Did you sixe sample enough to determine if they used different sizes to eliminate backlash.
2) Determine manufacture: they should help you with the numbers if it is a standarded loaded ball screw .
3)If you can not determine manufacture, then go to www.rockfordballscrew.com,click on their service manual...then click on assembly of a Standard Ball Screws..by following these instructions you can correctly "stuff" the ball nut to full. Using a lathe chuck to hold the screw while loading sure helps (along with vasoline,no phone , no kids and no significant other bugging you )
4) By experiance only, I have found that you can use a ball nut .0003 to .0005 oversize to eliminate back lash( if the nut and screw are in good shape) if that was the original intent to unload the ball nut.If accidental, and no damage is evident in the ball screw or interior of the nut, use the ones it came with.
5) The "start" and "finish" threads of different ball screw manufactures are all different.The active threads only include those that are between the start and finish of the return tube.Loading balls "above" the start of the return tube traps those balls without benifit of circulation.Loading "below" the start and return will only spit the balls out when you rotate.
6) other than that , ball screw loading is an art, more than a science, and good luck !

Adobe (old as dirt)

[Adobe Machine]

sorry, that should be www.rockfordballscrew.com



Adobe..old as dirt

[phantomcow2]

Thanks for the reply. The diameter was .125. In my new Nook ballnut the balls were .125", right on. In my older ballnuts, the balls were a couple tenths undersized. I am just going to buy some bearings frm Applied Tool and replace them with ones that are .125.

I grabbed a small allen key, would dip the end to get a little grease on there. Then grab one or two bearings, and place them inside one of the grooves so that the grase holds it in place. I just looked to make sure there were no gaps in any hte grooves where balls should be. I am pretty certain I got all the balls in, if not there are no more than 3 balls missing. Took about 30 minutes.

I am going to see if Applied has any balls that are ~.0003" oversized to replace the old ballnut balls.

[Adobe Machine]

If your supplier does not have .1253, go to www.salemballworldwide.com, look in their inventory "chrome steel,52100". All of their inventory in 52100 is grade 25 and above,plus very economical.I bought several sizes of .125+ up to .1257 and tried several combinations untill we got the right "feel".Testing in steel showed a back lash less than .001,even better in Alumnium.

As a caution, do not use a magnet to pick up and place the balls,this magnatises the balls, which in turn picks up slivers of steel and make them a part of the rolling process,prematurlay wearing the ball screw and ball nuts.

Adobe (old as dirt)

[BEARINGMAN]

Please remember, the smaller the grade #, the higher precision the balls. (grade 10 better than grade 25, etc.) Standard precision bearing use grade 1000 balls, and class 7 precision bearings use the grade 25. The grade also refers to the roundness of the balls, not the size. Rounder balls go faster and smoother.

[miljnor]

I am supprised no one said it earlier.....


I was born with one per nut, and 2 nuts (hopefully that means I am normal! )


sorry It had to be said!

Although you might ask next: How many nuts per thread??

I would have to answer at least one!

[fignoggle]

go to ebay and look for seller "toolsupply". i called around at bearing shops all over and some of them priced 1 ball at around $0.50!

then on a whim checked ebay and found this guy selling them in 100 lots. i was able to get a cheap rolled ballscrew/single nut to yield between 0.001"-0.003" (not too comfortable saying zero backlash). you can definitely feel the difference between standard balls and oversized.

in a 5/8"x5tpi, there's somewhere around 50+ balls. you can actually alternate between stock and oversized to give you more ball nuts to reload.

hope this helps!

[dertsap]

Originally Posted by miljnor I am supprised no one said it earlier..... I was born with one per nut, and 2 nuts (hopefully that means I am normal! ) sorry It had to be said! Although you might ask next: How many nuts per thread?? I would have to answer at least one!

ive chuckled everytime ive seen the title , i fanally decided i had to bite this one , you beat ,me to it, oh well i dropped the nuts ,i mean ball on this one

[S_J_H]

My Thomson 5/8" ballnuts have 68 balls. You can sneak in another 2 but I think it works better with 68.

Steve

[TommyB]

Steve,

What size are the stock balls in a thomson 5/8" , .200 lead nut?