Re: [CAD_CAM_EDM_DRO] spinning ball nuts

Seems to me that you can get away with the small diameter lead screw. The
nut will always be pulling against one end or the other and it will never
be pushing against the screw unless the end that it is pulling against
stretches. I would mount the motor next to the nut and drive the nut with a
gear tooth belt. The screw may sag a little but that should not matter as it
won't be very heavy for the nut to lift as it travels along.
Doug

----- Original Message -----
From: <JanRwl@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Saturday, February 07, 2004 3:17 AM
Subject: Re: [CAD_CAM_EDM_DRO] spinning ball nuts


In a message dated 2/7/2004 12:36:09 AM Central Standard Time,
plastiguy@... writes:
Besides the added design challenge of having the servo motor move with the
gantry that it drives, what snafus might I encounter with this approach?
That "design challenge" will indeed be the "SNAFU"! I still think you will
need AT LEAST a 1.25" O.D. screw! I built such a machine in '86
(126"-"X-screws") and I DID use 1.5"O.D. x ½" pitch ball-screws. Expensive,
yes, but it
worked!

The preloaded ("dual") ball-nuts were quite large over the ball-return
tubes,
etc., and it WOULD have been a challenge to rotate the nuts instead! You'd
also need DUAL thrust-bearings in addition to the axial bearings, or, just a
pair of angular-contact ball-bearings at each end (facing opposite ways).

Lossa luck! Jan Rowland


[Non-text portions of this message have been removed]



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