Post date: Jun 29, 2013 3:37:23 AM
...I've got a partially finished nut-turning assembly! This is the part of the machine that will couple the stepper with the Z axis rod. Since the rod is fixed in the carriage, the stepper will turn this tube, which contains a nut, and that will make the Z axis move. At least that's the theory.
Anyway, it took me several hours of careful lathe work to get the tube and ring shown below. The tube wasn't too bad- just turning down the outside and inside to make sure they're circular. The ring was a bit of a pain. Hindsight starting from a piece of thick-walled tubing probably would have been good, but I started with a hole-saw-cut chunk of 1/2" (I think) aluminum. I turned down the faces and edges of that to make as perfect of a cylinder as possible that nested nicely in the tube. The center hole was already started by the hole saw, but I drilled it out to 1/2", then turned it further to fit the nut.
The tube has kind of a rough finish. That's not really a problem, since it's not going to be sliding against anything, though I may want to make it look a little nicer before I assemble everything together. We'll see how sick of turning aluminum I get.
The three pieces fit together really nicely- almost no play at either of the two interfaces.