Re: [CAD_CAM_EDM_DRO] flat on shaft

Hi Peter,

YES! You do NOT want to put a non-flat shaft in a precision coupler,
and tighten the set screw!

What you want to do is drill a short piece of angle aluminum for a pair
of matching holes. clamp it down on the Sherline mill table. Bolt on
the motor, and motor is now secure on the table.

Make up a 1/2" OD x .25" collar, with a 1/4" hole, and a pair of 6-32
threaded holes, for setscrews (this is a fairly common stock item, used
to be lots of them used in OLD radios with dials and dial strings and
tubes, and...). Easy to make.

Then turn down and tap a 1/4" brass or aluminum rod 3" or so long for a
6-32 thread on one end (or use stock hex or round standoffs).

The rod goes into the collar. Yes, I know, don't tighten too hard, or
they won't come off (chicken and egg)! Make the collar loose if you
need to, and slip in a piece of shim stock if you're worried. The brass
or aluminum threaded end (cleaned up) will not usually mar a steel
shaft.

With the collar slipped over the motor shaft, you'll notice that the
collar will prevent the shaft from turning if you let it press against
the mill ways (and hold it there a little). It takes very little to
hold the shaft this way. Double ended shaft? even better. More room!

Now, you can use the mill to mill a flat on the shaft for about 3/4"
(take LIGHT cuts, and wrap the motor up in a plastic bag, if you're
worried), and probably .1" (maybe less) deep. Check out another shaft
flat, and copy it!

I have personally done this several times, and had no problems! You do
NOT want to clamp the motor in a vise!

HTH

Alan KM6VV
P.S. Sherline also sells flatted shaft motors, too!

cadcamcenter wrote:

>
> Hi,
>
> Sherline have some very nicely made motor mounts for their machines,
> plus solid coupler. Their item I am sure are machined to very close
> tolerance. Their dual shafted motors with a flat on the shaft.
>
> If one use a stepper with shaft minus a flat on their coupler and
> motor mount, will the set-screw cause a burr to be raised and thus
> difficulties in removing and/or remounting the motors? Anyone had any
> experience in mounting no-flats shafted steppers on Sherline's motor
> mount?
>
> Many thanks
>
> Peter