Re: [CAD_CAM_EDM_DRO] Re: unimat classic

Hi Wayne, Peter,

I just looked at the flexible shaft that came with my new Dremel, and
there is considerable windup. So I believe that option is out.

Do the handwheels come off? If not, how about a "cup", that could slip
over the handwheel(s), and a 4mm shaft on the back of the cup, where a
timing belt pulley could be mounted. How about a pix? I'll bet someone
on this list has some ideas!

Any cutouts in the handwheels? These could be engaged by tapered pins;
such that they add pressure as the disk they are mounted to is drawn up
against the handwheel. The disk would similarly have a 4mm shaft to
mount the timing belt pulley.

The handwheel could be direct driven, with a flex coupling connected to
the back of the drive disk. A plate would need to be mounted on the end
of the way, and spacers used to provide room for the flex coupling and
mount a second plate, which would then provide mounting for a stepper
motor (NEMA #17?).

Alan KM6VV


cadcamcenter@... wrote:

>
> "Wayne Bengtsson" <wbbengtsson@g...> wrote:
> > Hello:
> > As far as connecting steppers to smaller machines, one idea I had
> was to use short lengths of flexible shafting. I have no idea if this
> has been done before, or if it is even practical. Bad things include
> the flexible shaft torquing, increasing backlash effect. On the plus
> side, with the motors remotely mounted, you don't have to shift their
> mass.>
>
> Thanks Wayne. I think I'll try to find some flexible shafting that
> might be usable for this purpose. Maybe the Dremel flexible shaft.
>
> Below is the post I composed before I read your post. Anyway, here
> goes:
>
> Unimat I (Unimat Classic)
>
> WORKTABLE (Y-axis)
>
> SIDE VIEW
>
> |<------50mm-------->|
>
> ---------- ---------- -
> | _|..|_ | 16mm
> |_______. 0 ._______| _
> ....
>
> handwheel 29mm
>
> FRONT VIEW ....(hidden lines)
> ____________________
> __-- | ..................
> |__ \__| .
> | ...| ./\ /\ / approx 1mm pitch threaded rod
> | __|_.__\/__\/_
> | / |_.
> --
> handwheel
> outer diameter: ~29mm D-shaped
> inner diameter: ~18mm with set-screw
> hollow shaft outer diameter: ~8mm
> hollow shaft inner diameter: ~4mm (for threaded rod)
>
> Hoping for some ideas on how to attach a stepper to the Unimat I. The
> easiest I can think of is replacing the handwheel (unfortunately D-
> shaped) with a geared wheel to be driven with a belt connected to a
> stepper mounted on a plate riveted to the worktable.Where might such
> a geared wheel be available - SDP-SI?
>
> Maybe saw off the handle and glue/screw on a toothed wheel direct.
> What may happen if the centers are not concentric? Perhaps this is
> not critical as all that may happen is the belt just move "up-and-
> down" and "left-and-right" with small changes in the tension?
>
> FRONT VIEW ....(hidden lines)
> ____________________
> -- | ..................
> ~~| \__| .
> /\| ...| ./\ /\ / approx 1mm pitch threaded rod
> ||| __|_.__\/__\/_
> \/| / |_.
> ~~ --
> handwheel
>
> ~~ toothed belt
> /\
> || toothed wheel
> \/
> ~~ toothed belt
>
> Is Nema 17 small enough for a dwarf like this one, or would I need
> something even smaller?
> Any possibility for a direct drive with a properly sized motor/mount?
>
> Photos of the Unimat Classic can be seen at
>
> http://www.maxmax.com/fMini-mate.htm
>
> http://www.unimat.at/d_s_unim.htm