Making Your Own Helical Couplers

How would you tackle it.

I finally got around to putting a motor on one of my rotary chucks and
hooking it to a controller.  I think I could write the code by hand to
cut the helix with a small end mill, and use a combination of hand
coding and CAM coding to do everthing else except tap the clamp and
set screw holes on one of the mini mills.  Then do my tapping with the
little tapping head on the bench drill.  I do think it would be fairly
slow.

Is there a better way.  I know.  They aren't that expensive.  Just buy
one when I need it right?  LOL.  Two problems with that.

1.  I did buy a few of them a while back in what I thought was going
to be the most useful size.  I have used all of them on one project or
another now.  Every single one has been modified or I had to make an
adaptor.

2.  If I buy them to fit my current application I have to stop what I
am working on and work on something else.

I was thinking if I could premake a dozen of them at a time in a
couple standard "blanks" I could quickly bore each end to fit my
current application when I need one.  Maybe prebore them to to one of
the smaller standard bores like .250 or 6mm, and leave the very end of
the clamps connected until I bore them to the size I need.  Then just
cut off the end.