Well, not trying to be snotty toward everyone telling me I really want
an acme thread, but I did find it annoying to clearly describe what I
wanted and why I wanted it, and still be told that's not what I want.
I know those folks were trying to be helpful.

So I grabbed a box of misc gears, found a small SS pinion that seemed to
roll nicely over a 3/8-16 tap. Took all of 15 minutes to hack up a
really crude 'hobbing' fixture and 'hob' the gear. It rolls very nicely
up and down a 3/8-16 thread as a rack and pinion. When the gear is
locked, it'll act like a nut, allowing fine adjustment.

I WILL post pictures of this setup when done, as well as a shot of the
'hobbing' setup. It's now a done deal, I just have to finish my
brother's macro rig so I can start on mine...


Jon