Jinx wrote:
>
> > >Isn't that only about 7 revs/second? I don't think
> > >that is getting too scary mechanically. :o)
> > >-Roman
> >
> > Not mechanically, but a 2 meter diameter (1 m radius) moving
> > at 420 rpm is not to be messed with.
>
> No, I wouldn't want to cop a hit from it. I've got the main
> motor drive built using a 1/2hp DC motor on a steel frame.
> You definitely need it balanced and caged

I still think this is do-able. McMaster Carr
www.mcmaster.com
have bearing info with side load forces listed.

Your 200g is only 6 times higher than a standard
size 23 stepper motor with standard bearings.
Use a lighter motor with higher spec bearings
and its done. Remeber that spec is for continuous
side load and is conservative, you could go many
times that load if you are prepared to reduce
bearing life. Bearings don't self destruct if you
exceed loads they just wear out quicker. Some
CNC routers replace spindle bearings every month,
they run at MANY times the specced side load.

The only critical thing is the bits at the END
of the arm, the other bits only have low forces.
How much power does the small motor need? And
what speed, and (cough...) what does it all
do again? ;o)
-Roman

PS. Don't let the 200g scare you, i've worked
around inductrial machines for years, some of
the forces would be very scary. Even my racing
motorcycle's wheels when I'm doing 260kph on the
main straight every lap.

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