Re: Re: leadscrew bearings / machine design(P.S. correction)

Ballendo wrote:

>P.S.<snip>
>You can use a straight bore with two(2!!) expansion rings for the
>bearings to push against.

Ballendo shoulda wrote:

You can use a straight bore with GROOVES FOR two(2!!) expansion rings
for the bearings to push against.


P.S.S. More?! Yep, more. :-)

For the sake of complete-ness, there is another way "rigid" mounts
are made:

A hole through the mount block slightly bigger than the lead/ball
screw diameter.
A bore not all the way through the mount block which is the O.D.of
the bearings.
This bore is then threaded(fine threads)a little ways for a bearing
retainer ring.(similar to camera lenses).

The rest(leadscrew part) is the same as Jon described.

To assemble:
The leadscrew is put through the first bearing, which stops on the
"step" Jon described. The spacer(s)(between bearings, see below) is
placed on the L/S. The 2nd bearing is placed on the L/S. The nut
holding the bearings onto the shaft is placed and tightened. The
entire assembly is placed into the bore (with the threads). The
(camera lens-style) nut locks the entire assembly in place.

NOTE: If you just use one (inner race) spacer, you can adjust the
bearing pre-load with the "camera lens" nut. You can ALSO wreck the
bearings!
So...
A 2nd sleeve (sized to the O.D. of the bearings) is used. The
RELATIONSHIP (between lengths) of these TWO sleeves determines the
backlash/pre-load.

Take out the spacers and use ground face matched pair angular contact
bearings and you have a top of the line "fixed" mount.

Ron, I hope this all makes sense?