RE: [CAD_CAM_EDM_DRO]spindle plans (was VFD Selection)

Ballendo,

I checked again... I did not read far enough in the thread.
The earlier posts were unstable designs but I see that
evolved into a proper 3 bearing unit. The only thing I saw
missing was a light spring preload for the back deep groove
bearing- it floats, but still needs a mimimum axial load
to prevent ball scuffing due to internal clearance. Perhaps
it was there and I didn't see it.

And yes... I will again emphasize that this requires VERY
precise machining. As Marcus and I have mentioned such critical
work can be done with even small light lathes, ring laps, and
stones. It really hinges on the ability to measure. We are
talking tolerances here that many would find difficult to
repeatably measure even with a 0.0001" micrometer. It can be done
with a lot of careful hand fitting. That is almost a lost art
but threads like this can help preserve it.

Les

Leslie M.Watts
L M Watts Furniture
Tiger Georgia USA
(706) 212-0242
http://www.lmwatts.com
Engineering page:
http://www.lmwatts.com/shop.html
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http://www.lmwatts.com/forsale.html
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-----Original Message-----
From: ballendo [mailto:ballendo@...]
Sent: Monday, April 19, 2004 10:49 PM
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: Re: [CAD_CAM_EDM_DRO]spindle plans (was VFD Selection)


Les,

You lost me. It IS a 3 bearing design. Or is the face ground AC
bearing set considered "one" bearing?

This design has been used successfully on many commercial spindles
for years. If by three bearing you mean the ground faced set, another
bearing spaced from them, and then the third radial bearing for the
pulley end; I agree. That design is MUCH stiffer. AND MUCH more
expensive. Also requires a GREAT deal more precision in the making...

The design finally arrived at, is sold by some well known mfr's as a
separate spindle to "bolt-on" to industrial process machinery. I'd
certainly trust it for use in a small mill or as a bolt-on for a
gantry machine. I wouldn't use cat40 on it...

Ballendo