What size is CNC fusion thomson ballnut balls?

[alexccmeister]

Hi all,

I am thinking of loading oversized balls for my Thomson ballnut but I am not sure what size I should get. I am getting them from Toolsupply at ebay. Can anyone advise? Thanks in advance.

Alex

[Adamj12b]

I am also very interested in this, as I am also looking to do the same thing. -Adam

[kawazuki]

why not measure whats fitted standard and get several sets each a thou larger than the previous?

[Crevice Reamer]

Why not just ask Michael?

Email him at: support@cncfusion.com

CR.

[alexccmeister]

Originally Posted by Crevice Reamer Why not just ask Michael? Email him at: support@cncfusion.com CR.

Hi CR,

I did. Still waiting for his reply. May be he busy.

In reply to Kawazuki, I checked out Toolsupply on ebay. Great place to find ball bearings but unfortunately they don't have sizes that is slightly bigger than the next. Its much bigger. Its like in step of 3mm if I recall.

Someone mentioned here on this forum the ball bearing diameter for cncfusion thomson 5/8" ballnut is 0.124" in diameter. And they used a 0.125" ball bearing to preload their ballnut.

Alex

[alexccmeister]

HI guys,

Great news. Check out this page on ebay. Turns out Toolsupply has plus sizes bearings as well. So take out the balls from the ballnut and measure it, then figure out which plus size balls you need to preload the ballnut.

BTW, how much bigger should the ball be if the the original size is say 0.125"? Thanks.

Alex

[alexccmeister]

Hi guys,

Guess what? I had these nook ballnuts that I bought from Homeshopcnc a while back cos I wanted to make myself a large footprint mill out of epoxy. Anyway, I tested them on my cncfusion ballscrew and they fitted much better than the thomson ballnut on the 5/8" ballscrew. Very little or no back lash. I am now thinking of swapping the thomson ballnut with the nook ones and see if there is any backlash. I think the nook ballnut may have larger balls than the thomson ballnuts.

What do you guys think?

Alex

[kawazuki]

Thats a possibility - most nuts will be supplied with a ball dia to suit the design spec of the screw its being fitted to, I believe Fusion use Nook screws so sounds like a match. Preloading is trial and error, stepping up the ball dia a thou at a time until the nut is no longer smoothly functional, then its mix and match or reload with last best diameter balls.
With rolled screws it'll always be a lottery over the whole screw run, so sometimes best to accept 0.0005/0.001 lash if the movement is smooth and CONSISTANT over the whole operational screw length?