Arm assembly

Progress was halted over the weekend due to me running out of bolts and nuts, mostly 3mm, but also I did not have 40mm and 100mm M8 bolts for the arm joints (I thought I had).  I did add the stepper motor in their mounts yesterday (complete with the drive belts), as well as the "A" sections of both Theta and Psi arms.

This afternoon/evening I added the "B" sections of the arms, including the tool head with J-head mounted.  I pulled the hot-end and z-axis stepper motor wires through the hollow centres of the Psi arms, and down to the lower frame through one of the support pipes.

As Francois mentioned in a comment, it is not simple to pull the wiring through the pipes afterwards - remember to fit a piece of string/wire during assembly!  I actually found it easier to work from the bottom upwards (I pushed a piece of white twin flex through and taped my wires to the flex with insulation tape before pulling it down through the pipe.

Difficulties in assembly:

 I had a few hassles during assembly:  the biggest of which was the fact that the top platform was not parallel to the bottom one.  It was sloping down towards the back (enough to have a drill bit roll down).  I must check the pipe lengths - maybe I misread and cut the longer pipes too short.

I fixed SOME of the slope by fitting 28mm washers (1.5 to 2mm thick?) on either side of the ported pipes to tilt it upwards.  It is not level yet, but close.  I also tilted the z-axis motor slightly to level it by fitting two 4mm washers underneath the rear corners when I screwed it to the platform from below.

The second difficulty is that I broke two of the smooth rod "receptacles", one on the top and one of the bottom brackets which accepts the rods and drive shaft bearings.  These shear fairly easily from the flat bit, be careful.

What remains to be done is the bed platform.  I cannot currently fit that as I do not have a spring to take care of the backlash, and then it is on to the RAMPS wiring.  The heated bed was fitted to the aluminium platform with three spring-loaded screws today, that still needs wiring as well. I will probably be working on that over the next few evenings.

I also still have to sort out the extruder - I got the 1.75mm extruder, and need the small bearings, the hobbed drive gear, and a second (4mm) length of PTFE tubing to fit it all.

Oh, and the Kapton tape and thermistors were in the post box today.