Re: Bridgeport retrofit servo questions

Jon,
I read with great interest everything you write on this board, but I
believe you did this man a minor injustice. He made no reference
what-so-ever to mounting a ballscrew to a motor in such a way as to
handle ANY thrust load. His comment was only in regards to the
encoder. You are busy, I know, and probably cannot take the time to
reread the post, but it appears you shot a man out of the saddle when
he was not even on a horse. It is a simple misunderstanding, I am
sure. I hate to see feelings hurt over a mistake. Meanwhile, please
keep up the good work. I learn vast amounts of information here.

Randy

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Jon Elson <elson@p...> wrote:
> Dan Mauch wrote:
>
> >Not sure why you replied with your comments about leadscrew axial
thrust. My
> >statement was only a general statement that a PDMC motor should
not have
> >more then .005 because of the effects on encoders. It was meant as
a heads
> >up for when they are looking to purchase a PMDC motor for use in
any servo
> >applications. You are correct that motor bearings should not be
used to
> >handle the axial load of a leadscrew
> >
>
> A lot of people try to get away with using the motor as the thrust
bearing.
>
> Most motors with ball bearings have a preload spring (wave washer)
to
> constrain
> the armature. A sleeve-bearing motor would not, but it is a poor
choice
> for a
> positioning servo anyway.
>
> Jon