The couplers between the Z-axis motors and the threaded rod that acts as a screw arrived on Tuesday night. On the couplers that I ordered, the holes in either end had a diameter of 6mm so in order to connect the rod to the couplers and the motors some machining was required. Peter came to the rescue once again by turning down the ends of the threaded rod to 6mm and turning a spacer to fit on to the 4mm shaft of the motor to enlarge the OD of it to 6mm.
I only needed two of them but at $1.50 each ordered 2 extra, Probably a good thing as the machining on them is less than accurate. You can see on the top of the one on the left the threading for the grub screw has broken through the top face.
After a few firmware tweaks to get the Z-axis moving at the right speed with the right steps per unit this was produced
One very rough 20 x 20 x 10mm cube.
Both the belts on the X and Y axis need to be tightened, the bed needs to be leveled and the frame squared up still but as a first print with all this alignment / calibration stuff to do I’m pretty stoked. Looking at the top of the cube it looks like the extruder may have stalled a few times, I suspect this was because the motor controller was overheating and shutting down, Since mounting a fan above the RAMPS board this hasn’t seemed to have happened again.