Roller Bearings link ? ( was Bad Bearing ( was Re: stuck stepper

It is nice having a lathe. making things like a bearing tool takes a
few minutes and the results are great.

I ordered some bearings so that part is all but done.

I pulled out the rotor when I noticed it had been rubbing on the
stator. a visual inspections was in order. So mag or de-mag that
point is mute. Besides, since the motor is potentially trash, the
price is well worth my learning. or my learning is about the same
price... something like that.

It seems that the rear bearing may have frozen, then spun in it's
housing before the rack gave up. since it appears to have spun in
the housing it needed a little persuation to come out. now it will
slide from the pressure of the spring washers.

Dave

--- In CAD_CAM_EDM_DRO@y..., "Les Watts" <leswatts@a...> wrote:
> A bearing seating tool is a good idea. Sometimes you get lucky
> and a piece of copper tubing faced off in the lathe is the right
size.
>
> As far as ABEC-1 for stepper motors....
>
> I would guess 90% of all stepper, servo, or induction motors
> use ABEC-1 tolerance. For your bearing size that means max runout is
> typically 0.0004"! About the only reason to use something higher is
> if it is in a motorized spindle or something. Also, I have found
very
> few shops that can properly machine a housing for something
> like ABEC-7.
>
> The fact that there is no mention of accuracy in the part number
> means it is prob default ABEC-1. In fact I have never seen better
than
> ABEC-1
> in any servo or stepper that was not also a unitized spindle.
>
> Oh one other thing... There has been much mention of partially
demagnetizing
> steppers by removing the rotors from from the housing. I cannot
confirm this
> but it might be prudent to keep the rotor in the housing while
replacing
> bearings.
>
> Les
>
> Leslie Watts
> L M Watts Furniture
> Tiger, Georgia USA
> http://www.alltel.net/~leswatts/wattsfurniturewp.html
> engineering page:
> http://www.alltel.net/~leswatts/shop.html
>
> ----- Original Message -----
> From: "turbulatordude" <davemucha@j...>
> To: <CAD_CAM_EDM_DRO@y...>
> Sent: Thursday, September 12, 2002 7:02 PM
> Subject: [CAD_CAM_EDM_DRO] Roller Bearings link ? ( was Bad Bearing
( was
> Re: stuck stepper
>
>
> > Hi Les,
> >
> > I had assumed that there was some higher standard for steppers
than a
> > plain ABEC-1 electric motor bearing.
> >
> > The outter race does seem to be a very tight slip fit and the fit
on
> > the shaft is also a thight slip fit. the shaft out by hand, had
to
> > persuade the bearing in the housing to come out.
> >
> > I'll turn a small bearing seating tool for insertion. I do know
that
> > only the outter race can be used for pressing it into the housing
or
> > the inner race when pressing on a shaft.
> >
> > Thanks,
> >
> > I'll get the bearings with confidence.
> > BTY. I assumed that the NMB was the manufacturer.
> >
> > Dave