Alternative milling spindles for the Nomad

In my other thread I discovered that after adding an ER16 spindle holder, I have 55µm of runout, which is… Not optimal…

I could just deal with the runout but I’ve been thinking about how to retrofit a different Z-axis onto the Nomad. Looking at Vince’s thread, it looks like the things I’d need to do are:

  • Replace the X-axis lead screw with a ball screw. Also a NEMA23 stepper.
    • Make a ball-nut adapter (some simple machining on the Nomad and some thread tapping (by hand))
    • Buy a ball screw
    • Buy a new stepper
    • Buy a shaft coupler
    • Cost: Few hours machining time, ??? for a ball screw + supports, $20 for a stepper (though maybe while I’m here I should go closed-loop) and shaft coupling
  • Rinse and repeat for Y-axis?
  • Replace the Z-axis carriage
    • Buy linear rails
    • Mount linear rails to something (X-axis carriage? New plate attached to X-axis carriage?)
    • Machine new Z-axis carriage (just a 12mm-ish Aluminium plate with some holes in?)
    • Attach new carriage to rails
    • Replace lead screw with ball screw?
    • Replace NEMA17 with NEMA23?
    • Cost: Many hours machining time, maybe a stepper, ~$70 for a pair of linear rails

And then I can mount whatever I want to the Z-axis, even a holder for the stock spindle and its BLDC motor if I want (though I’m thinking 800W watercooled spindle from Mechatron or G-Penny).

@Vince.Fab what do you think? Am I missing anything? In particular, did you upgrade the Y-axis as well? How does that look?