Re: [CAD_CAM_EDM_DRO] re:Re: leadscrew bearings / machine design(2nd gif dwg)

I'd still do it "my" way. The only change I might make would be to use would be a Timken tapered roller bearing instead of an angular contact ball bearing.

The drill heads I referred to earlier generally use a straight roller bearing on the rear end of the shaft and two or three angular contact roller bearing on the front (the end that takes all the thrust loading) end. The size and number of bearings used of course would depend on spindle size and expected thrust loading...with a safety factor bult in.

These designs have worked well for well over fifty years, and I expect will continue for many years to come.
-----Original Message-----
From: JanRwl@... <JanRwl@...>
To: CAD_CAM_EDM_DRO@egroups.com <CAD_CAM_EDM_DRO@egroups.com>
Date: Tuesday, October 24, 2000 10:00 PM
Subject: Re: [CAD_CAM_EDM_DRO] re:Re: leadscrew bearings / machine design(2nd gif dwg)


Sorry to disagree with learned wizards, but, though very, very stupid and
very, very, very ugly, I had been there, done that, and the most-rigid and
"bestest" way to do the ends of a lead-screw are to have two SEPARATE
angular-contact bearings on EACH end (total, four per screw!), each pair set
at least twice the screw-major-diameter apart (between them), or, at least
twice major screw-dia. plus one bearing-thickness "on-center". Really! Just
havin a pair of bearings with "no" space between them (oh, maybe just a
spacer between the two inner-races) is no-where NEAR the same as the
"spaced-apart" pair! Unless you are talking a total screw-length no more
than, say, ten times the major-dia.!

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