Z Axis


Please do not attach anything to this assembly above the tool mount.  You will see lots of images of people attaching cable chains, wires, and vacuum hoses to the motor mount. This is the absolute worst place on the entire machine to attach anything! It will act as a torque multiplier and completely ruin your accuracy/precision. Anything necessary should be attached to the main gantry assembly there is lots of room on the XYZ piece.



Insert the 4 nuts into the nut traps, if they aren’t a tight fit a drop of glue here will help in assembly in the next step.



Insert the NutTrap into the Z Rail 1 at a time and use the .75″ screw to attach the ToolMount. I tighten these screws to set the nuts into the NutTraps then back them out to leave this extremely loose for now. If your nut traps don’t fit your rails thickness well Geodave made a nice parametric part here, http://www.thingiverse.com/thing:907882



Press the bearing into the Z-Lower bracket. Make sure it is seated all the way and not crooked.



Slide the Z-lower bracket onto the z rails as shown. Slide it a few inches past where you think it will end up. Use no screws yet.



Use 3 M3x10mm screws to attach the stepper to the Z-Motor bracket.



The current kit includes an aluminum coupler and leadscrew. Insert the coupler so the stepper shaft is 3/4 the way through. Tighten the first grub screw onto the flat of the shaft, then snug up the second one.



-If using threaded rod- Slide the Pineapple Coupler onto the Stepper shaft The aluminum coupler is not a good choice for 5/16″ allthread. If the stepper half is long enough make sure not to go past the halfway point (inner ridge). If you have a “D” cut stepper shaft I orient the flat at the coupler seam. Use no screws at this point.



Slide the Z-Motor bracket onto the z rails approximately (if you cut your rails carefully) flush with the rail tops. No screws at this point.



  • At this point I hang the assembly off the edge of a table (A glass or metal table makes this easy). Make sure the rails are sitting flat on the table, and tighten the ToolMount screws.
  • Check again, are the rails still flat? Sometimes they will slightly twist and you can easily fix it here, Much easier than on the machine.
  • If the rails are good, add the .75″ screws and nuts to the Z-Motor bracket only, snug slightly.
  • Check again, are the rails still sitting flat?



  • Make sure the leadscrew is touching the stepper shaft. (allthread)Thread the lead screw/all thread into the coupler. Make sure it is all the way and should hit the inner ridge/stepper shaft (allthread).
  • Give the coupler a slight stretch to ensure a tight connection.
  • Tighten the coupler grub screws and make sure the lead screw rotates smoothly with little wobble. Now is the time to fix it if it is, loosen the grub screws and rotate the screw and tighten it again until it spins true. (allthread)Snug this up with the .75″ screws and lock nuts carefully. Snug to tight is good, cracks are bad! The lead screw should be nice and parallel to the z rails and not bent.(allthread)
  • Make sure to lube the screw, White lithium is the most common.
  • If the leadscrew is not going through the bearing, sand or file it a bit (or a lot). It is an exact fit and we all know that is never a good thing. 8mm ID bearing, 8mm OD Leadscrew. You can try a few different bearings or the other end of the leadscrew. Either way sanding 1″ or so of the end will make it work well. The bearing is there to support the coupler, not guide the leadscrew, no accuracy loss.
  • Pay attention to the cut calculator, Make sure the leadscrew is at least that long, but no longer than the bottom of the Z rails.



  • Pull the Z-Lower bracket up tight against the Coupler this should take care of most of the stepper slop (the lead screw can not move in either direction). Make sure the brackets are parallel with each other (you can measure each side near the screw holes).
  • Once again are the rails still sitting flat?
  • Add the screws and nuts and snug slightly.
  • Final check are the rails still flat/parallel?