Thread: I need help with my FK12 bearing block

I purchased some a few months back (two sets of FK12 Bearing Blocks), they had standard bearings instead of angular contact bearings in them, and the spacers were just complete junk, that's not to say you got the same junk but just open them up and take a look, bearings should slide right out.


BTW it's about time you got stuck into that mill and finished it

Peter,
I found they needed shims between the inner race of the bearings. I used brass shims and made them with an hollow punch.

My blocks benefited from shimming. I used a soft drink can cut with scissors. A bit tricky to do but it helped significantly.

Thanks for all the replies.

I'll pull it apart on the weekend.

Cheers,

Peter

If there is a large amount of backlash in your nut then you can take the backlash out of the nut if you have room by putting a second nut under tension

Russell

Hi Russel,

Thanks, one of my options is to get some double ball nuts from linearmotionbearings2008.
Hopefully I can use the nut on my existing screws.

Paul suggested that I check that I've installed the AC bearings in the correct direction as well. I think I did but I need to check it.

Cheers,

Peter

Do the double ball nuts remove all the backlash?
I used 2 nuts tensioned apart to takeup the backlash has work very well for many years.

R

I believe that they do. I'm not up on how it is done though.
3 Double Ball Nuts Double Ballnuts Ball SCREWS1605 2005 C7 for CNC Router | eBay

I could do it the way you suggest. That way it wouldn't reduce the travel.

The ballscrew mount is threaded so I could possibly;

1. use a longer bolt to extend through the block
2. use a threaded rod with nylock nuts on either side
3. use shorter bolts screwed in from each end. (the mount block may not be wide enough)

What do you use to tension the 2nd nut?

Cheers,

Peter

X-ScrewInstalled.jpgX-ScrewInstalled2.jpg

I used some heavy duty Belleville washer, there under the 2 nuts on the left (2 washer on each side) in the photo attached
The gap between the left ballnut and mount is there to allow for the small varation in the ball screw. This movement stops the ballnuts jamming up but take out all of the backlash.

Hope you can follow how this works......

R

Found this photo of a different way of mounting second ballnut

Hi Russel,

Thanks for that. It explains it perfectly.

Cheers,

Peter

If you use a fixed spacer I think you need to ensure rotational alignment stays fixed. I'm not sure if using springs removes this need - probably.

Just an FYI.
My friends in the UK, no longer purchase from linearmotionbearings (Chai).
They now purchase from BST Automation on Aliexpress, and find the prices as good or better, and the components to be far superior.

Hi Gerry,

Thanks for that. I've looked at BST but haven't had a chance to purchase yet.

Cheers,

Peter