On 1/15/2018 9:57 AM, Gunner Asch wrote:
On Sun, 14 Jan 2018 13:25:59 -0700, Bob La Londe
wrote:

I'm learning a lot... like you hardly need any torque on the thrust
bearing retaining nut on this KMB1. I learned how to make new tab lock
washers too since nobody stocks them, but several say they can get
them... eventually. I even learned what the X axis is supposed to sound
like with good thrust bearings. It never really had any problems, but
its sure sounds a lot smoother now. Obviously the bearings were bad.

With new thrust bearings on the Y-Axis its pretty smooth now too, but
only for about 7/10 of a turn. Then it pulses. Its actually a lot
worse than it was before. Before I could see a little flutter about
every 1000 steps or so on the scope, but the machine appeared to move
smoothly. I guess the Y-axis thrust bearings were so wore out that it
allowed it to move smoother. With new fresh bearings it pulses badly.
And no its not a matter of tuning. As near as I can tell the ballscrew
is bent and its binding as it turns. That would sure explain the
chatter I saw before. Now its unusable.

The bad part is I don't know how to remove the new bearings and save
them. The obvious way to pull the bearings pulls the rear bearing apart
when you take the housing and bearings off the shaft. So... even if I
find a good replacement ballscrew I'll wind up having to chase down
another set of bearings too.

Of course I have one piece to make to finish a job that is just a little
too big for the little mills.

DANG-IT!

Dont dispair quite yet...ballscrews can..can be found cheaply enough
both on Ebay and other locations.


http://www.practicalmachinist.com/vb...screws-232777/


https://www.ebay.com/sch/i.html?_fro...ews&_sacat =0


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Yep. Lots of options. I'll look at some of the sources on the PM
thread with more care in a bit.