I was faced with a similar situation when I wanted to adapt my benchtop
drill press to operate by a hand crank for using the drill press for tapping
holes.

I added a hub/puck of aluminum round stock to the top pulley edge (extending
a flat, thick surface above the spindle pulley) and drilled it to accept 2
pins, which the arm for the crank would have, to facilitate easy
installation and removal of the crank.
On the DP I have, releasing the quill return spring is just a matter of
removing a nut on the spring cover, so it's a fairly simple transition.. and
man, I like simple (just my speed).

After cutting a hole in the belt cover over the hub, I'm able to (First)
unplug the power cord, then release the drive belt, close the cover and drop
the pins of the hand crank into the holes in the hub, for tapping use.
The DP table vise can hold the workpiece in any position, so tapping any
part is very easy to accomplish.. no leaning sideways to try to get a tap
started at a weird angle or various other stunts which sometimes seem
reasonable, heh.

Anyhoo.. a simple modification for utilizing a hand crank for your lathe
will very likely occur to you.. and maybe when you're not even thinking of
it.
(and I hope it will happen at an appropriate moment, wink-wink,
nudge-nudge).

The expanding collet type of spindle adapter may have worked if I'd have
pursued improving it, but I had a shift in ideas when I recalled the type of
joint used on my bike decades earlier, so I went that route.

Another great aspect of metalworking is that scrap from one project has many
possibilities for another part of a new project.. there are no bad parts in
as much as they are excellent learning opportunities.. win-win, as they say.

Are you feeling enthusiastic yet?

--
WB
..........


"Bob S" wrote in message
...

I understand. Nice clear description.

It is interesting that the expanding collet didn't work as well.
Torque-holding ability ought to be proportional to the outward force,
which ought to be greater with the expanding collet because it
probably has a much shallower angle than 45 degrees. Probably there is
some secondary effect that I am not thinking of.

The left end has the "spindle gear" (actually a timing belt pulley) at
the end, with essentially no free space beyond it. In normal turning
the belt is on the outer end of the pulley. For screw cutting it sits
a little further in, some one could think about clamping a handle to
the pulley, but that is a little worrying, and besides there are two
different pulleys for inch and metric threads.

It think that the inside bore is the only attractive scheme.

Bob