T
Tim Hubberstey
Jim said:"Pricey" is right!
I'm gravitating toward
stepper-motor/belt-drive/ball-bearing-drawer-slide/some-kind-of-sensor
approach.
Looks like I need about a ft-lb or so of torque, 3.6° would do.
Sources, suggestions?
How about a stepper motor with a direct-drive connection to a piece of
Redi-rod (that's what it's known as in Canada - threaded steel rod up to
36" long). Use a nut welded/soldered to a pushrod as an actuator or
drill and tap your actuator directly. 0.25" rod has 20 threads/inch ->
0.05"/revolution. Your 0.010" resolution only requires 60-degree steps.
Measured backlash on a random sample of 0.25" bolts and nuts from my
junk drawer appears to be around 0.004".
This is a very standard way of converting rotary motion to linear
(lathes, old floppy drives, etc.). You might even be able to salvage the
head positioner out of an old 8" floppy drive. Newer floppy drives use
taut-baud positioners which wouldn't be as easy to hack.