Ballscrew Support Bearings - Angular or Self Align or ??

[routercnc]

Hi WilliamTurner1

You only need the ballscrew axial support at one end, usually the stepper motor end. The other end is floating. By this I mean the thread is turned down to a plain shaft which sits inside a simple ball bearing, and can slide in and out if required (see some earlier posts about temperature change effects etc.). This cuts your axial support requirements from 6 to 3, since the floating end only needs radial support.

I simplified this further and left my 16dia ballscrew unmachined and mounted it into a 16mm ID bearing. This only needs to provide radial support, so they are quite cheap. Works well for me.

For alignment I would suggest mounting the floating end on a plate which is adjustable in as many planes as you can design in. You can then fine tune the position during running trials.

As Gary suggests, you can buy these as kits. Search for BK12+BF12 which are the full support and floating support bearings as a set.

[williamturner1]

Hi WilliamTurner1

You only need the ballscrew axial support at one end, usually the stepper motor end. The other end is floating.

For alignment I would suggest mounting the floating end on a plate which is adjustable in as many planes as you can design in. You can then fine tune the position during running trials.

Magic! Thank you for confirming. I had figured as much looking at a THK 1m 1605 I have which has a floating bearing at its end (10mm bore vs 12mm axial bore) which is free to move in its housing, the other end is a beasty axial with double bolt holes.

Now I've got bearings and ballscrews sorted I need to sit down, do the calculations on motors + feedrates and also sort out drive (belts).

When turning the ballscrews (12mm bore + 12mm thread) should I also design in a woodruff key?