Ignoramus23245 wrote:
On 2010-12-12, Wes wrote:

Ignoramus13683 wrote:


On top of the head, the pulley shaft is hollow and I can mount
something in there, but then I would have to account for the back gear
and it is slightly messy.

A rod, very close fitting, with an o-ring groove and o-ring to cause it to grip to the
hollow shaft. Use more o-ring grooves and o-rings if you have slippage during start/stop
Easily removable.

What I'd do is make an expanding inside collet. Turn material to just
fit the ID of the spindle. Drill the canter,
then tap for a suitable thread. Then, drill and bore a taper in the
ID. Finally, slot the part with two slots at
90 degrees, on the end with the taper, down to where the thread starts.
Now, make a screw that fits the
thread and matches the taper. When you screw the tapered screw in, it
expands the collet, locking it into the
work. I've made these for some custom turning projects where I wanted
to face both ends and turn the
entire diameter of a part in one setup. They worked like a charm, and
were not hard to make. It almost takes
longer to explain than to make.

As for your specific job, I'd put a slot in the bottom of the collet so
a screwdriver can be stuck up into the
spindle to hold the collet while you tighten the top. You could make
the rod that drives the encoder be the same
part as the tapered screw that expands the collet. It might be easier
to make the encoder move up and down than
to use that ball-spline.

Jon