Z-Axis Assembly - Threaded Rod and Couplers PDF Print Email

For this part you will need:

  • 8x M3 Nuts
  • 4x M8 Nuts
  • 4x M3x10mm Cap Screws
  • 8x M3x22mm Cap Screws
  • 2x M8x210mm Threaded Rods
  • 2x 8mm Inside Diameter Springs
  • 4x z-half-coupler-8mm-5mm printed pieces


This is the final step of the assembly for the axes.  In this part you will be putting the x-axis onto a couple of threaded rods that raise and lower the whole x-axis assembly we finished in the last step.  This drives the z-axis for the printer.  As far as tools go, we will need a 2.5mm allen wrench to tighten cap screws and a level to make sure that the x-axis is horizontal.  This is what the printer will look like with all the axes on:


 You will start by getting the threaded rods and the couplers ready to put on.  You can get the threaded rods ready by threading an M8 nut about 1/3 of the way onto the threaded rod.  You may want to check to make sure that the nut spins easily up and down the threaded rod.  If it sticks somewhere, this could cause the z-axis to jam, which you don't want.  This can usually be resolved by trying different M8 nuts until you find a pair of M8 nuts that work well on each of the threaded rods.  Once there is a nut 1/3 of the way onto each of the threaded rods, put a spring onto the longer end of each, and then set them aside.  Now for the couplers, match up two of the z-half-coupler-8mm-5mm pieces so that the ends match up.  Once they do, put four M3x22mm caps screws through the holes in both pieces, then start an M3 nut onto the end of each.  Do the same thing with the other two z-half-coupler-8mm-5mm pieces.  The parts are ready to put on and should look like the ones in the picture below.


Take the longer end of each of the threaded rods(the end with the spring) and put them down through the hexagonal holes in the x-end-motor and x-end-idler pieces.  Put an M8 nut onto the end of each of the rods once they are through.  You need to thread the nuts on the bottom up so that they will go into the bottom of the x-end pieces.  It will be easy in the beginning, but once it's been threaded far enough you will have to push the M8 nut on top into the hexagonal hole to compress the spring a bit and continue tightening the bottom M8 nut.  Make sure you do not push down so hard that the spring pushes through the support in the middle of the x-end piece, this breaks the piece and you'll need a new one.  It's tight enough when you let the bottom M8 nut pop up into the hexagonal hole in the bottom and the top M8 nut is still a little ways into the x-end hexagonal hole on top.  It can be tightened more later if it needs to be.  Once both threaded rods are into the x-ends, put the larger end of the couplers onto the top of the threaded rods as far as they'll go on.  It may be easiest to thread them on.  Push the smaller ends of the couplers up onto the motor shafts as far as they'll go and start tightening down the couplers evenly.  The best way to tell that they are going on evenly is to look at the gap between the two coupler halves.  Once they start getting tight, look into the gap between the pieces and make sure that the motor shaft and threaded rod are still all the way into the couplers.  Finish tightening them down.  Rotate each of the threaded rods back and forth a little bit to make sure that the x-axis goes up and down and that the M8 nuts stay inside the x-end pieces.  Make sure that your printer is on a level surface, then put your level on the x-axis to make sure that it's horizontal.  You can adjust it by turning the threaded rods you just put on.  The axes are now all on and we can start putting on the electrical items for the printer.

In this next step, the extruder will be put on