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View Full Version : Securing and Aligning Ballnuts



WandrinAndy
24-08-2012, 02:49 PM
I've seen and understand the recommended method for aligning BK and BF blocks... first the fixed end and then the floating end... but I've never seen a ballscrew, ballnut, or ballnut housing/support in the flesh so to speak, so please excuse my thicko questions.

The 1605/1610 ballnuts I've seen on the web seem to have a outer diameter of 28mm, and the ballnuts and ex-stock ballnut-housings/supports each have six matching bolt-holes.

Am I right in thinking that none of these bolt holes are threaded and that through-bolts are used to secure the ballnut to the housing, which allows for a very small bit of alignment adjustment?

Can custom-machined housings be made to allow for a greater degree of adjustment?

Also from what I've seen, the ex-stock ballnut housings seem to be a lot broader than many of the custom-machined housings... Is there a reason for this?

JAZZCNC
24-08-2012, 04:26 PM
Am I right in thinking that none of these bolt holes are threaded and that through-bolts are used to secure the ballnut to the housing, which allows for a very small bit of alignment adjustment?

Yes small degree of adjustment can be made.


Can custom-machined housings be made to allow for a greater degree of adjustment?

It's Custom to your requirements so can be anything you like.!!


Also from what I've seen, the ex-stock ballnut housings seem to be a lot broader than many of the custom-machined housings... Is there a reason for this?

Not sure what you mean by Ex-stock has there are many designs and methods for ballnut housings.?

WandrinAndy
24-08-2012, 05:49 PM
Not sure what you mean by Ex-stock as there are many designs and methods for ballnut housings.?

Should have said commercially-available instead of ex-stock... Many of them are about 40mm wide, but the custom made jobbies often look like they're about 20mm wide where they attach to the gantry end plate.

In my attached pics the green more or less replicates the commercial size internal dimensions, and the orange is what I'm thinking of getting machined to give a full 4mm of adjustment all round, and think it will still be plenty strong enough using washers, but am not sure?

gio666
10-09-2012, 10:51 PM
The Ballnut housing should be tight and slip fit for ballnut. The all adjustment is made to end of ballscrew end housing. Both end bearing then will be in line with ballnut housing . It is the easiest way to line up all parts of ballscrew

WandrinAndy
14-09-2012, 07:10 PM
The Ballnut housing should be tight and slip fit for ballnut. The all adjustment is made to end of ballscrew end housing. Both end bearing then will be in line with ballnut housing . It is the easiest way to line up all parts of ballscrew

Thanks, I can understand that the ballnut must be tightly secured to the ballnut housing and at 90deg to the ballscrew, but afraid I still don't get why the ballnut needs to a be a slip fit into the housing if that is what you mean?

I would like to have the housing machined to provide plenty of one-off adjustability to cover for the likely inaccuracies in my DIY build with minimal tools... The alternative as I see it is plenty of shims and/or to change my design.

gio666
30-09-2012, 12:31 AM
IF you make the ballnut housing tight fit, then you will only need to adjust the 2 end, which will make it a lot easier than trying to lineup all 3 points . If designed right you should not need shims or anything. You will have about 1mm adjustment on each end with clearance holes in ballscrew end housing bolt holes.

gio666
30-09-2012, 12:39 AM
Here you will have easy adjustment with housing and not ballnut itself

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