Fabrication
After several iterations, I was able to settle on a set of components for the project. Here is an image of all my attempts to get this right.
Figure 9.8 – Parts from the prototyping effort
Once you have all the parts fabricated, you can go ahead and do some test fitting before assembly. Here is my frame (I decided I don’t need the “tail stock” portion of this for my purposes).
Figure 9.9 – Test-fitting the axis frame
You can see how I had to do a lot of filing to get everything to fit properly, but that’s only because the tolerances are so tight. You can always experiment by changing the scaling to go down by fractions of a percent, but that seemed like a long and drawn-out process when I could get things done faster with some post-fabrication trimming.
Here is a parts list for the 4th axis. You should be able to use any NEMA 17 stepper motor, and you are likely to have...