On Wed, 28 Oct 2009 01:57:44 -0500, cavelamb wrote:

Ian, you gave me the germ of an idea, but again, implementing it is the
question.

I had the problem over constrained (as usual).

Mcmaster ruined my bright idea.

Thread rod couplers aren't all that long. Now, it I could find one 6 or
8 inches long???

You could use the screw and nuts from a wood clamp,
if you invert the arrangement you show in your picture,
http://www.home.earthlink.net/~capri26/#tiller. That is,
put the clamp screw in place of your tube, and put tubes in
place of the threaded rod, with the clamp nuts captured in
the ends of the tubes. The wheel suggested by Gunner could
be fastened at the center of the clamp screw.

--
jiw