I've used the tracking number to redirect them to my address - I fancy some new ones

RH Front Z Drive Bearing Block.

LH Front Z Drive Bearing Block.

Back Z Drive Bearing Block.

Now printing in rigid.ink transparent orange like the rest.

The rods have arrived but I'm having trouble getting into the packaging!!

Managed to get inside and get the rods and nuts out

Nuts are 12mm diameter shank so that was a good guess   Now printing one of the nut blocks.

Production is progressing well   The so-called 1000mm rods are actually about 10mm shorter but that doesn't bother me as I shan't be using the whole metre anyway   I though the little holes round the edge of the nuts were threaded but they're not.  Just plain holes about 3.5mm diameter.  I had planned to attach adjuster wheels with screws but instead I think I'll just 3D print pegs on the wheels instead.  No problem and saves assembly time.  I shall print the adjuster wheels on my Mini printer for greater resolution and I can do that while the Titan is printing the nut blocks.

Made a mistake in the design of the back bearing blocks.  Needs the bearing 10mm nearer the edge.  Re-design coming up...

Photo of the Z level adjuster wheels - top and bottom.

Gradually designing & printing all the parts needed for the Z drive.

Here are some photos of the back Z drive blocks also with XY idler pulleys.  Top views and from underneath showing the adjuster wheels.

Just printing the last piece to complete the Z drive.  Photos to follow shortly.

Here's a photo of the top of the printer with the Z drive belts, pulleys and rods plus the XY frame etc.  The XY frame which is also the Z carriage is shown very near the top here where I adjusted the height at the four corners with the adjuster wheels (yellow) to level the carriage.  It won't come up this far during printing due to the space required for the bundle of wires and water cooling tubes.  The belts already have some tension and that may be enough but I have planned for tensioning idler pulleys if required.  The amount of wrap around the timing pulleys seems entirely adequate.

X, Y and Z motors connected plus power to the Duet control board and been testing the Z drive.  Needed to increase the motor current but it's working.  The timing belts are working fine with the present tension.

X, Y and Z now moving correctly   One motor needed reversing.  Probably not surprising as one motor is upside down   I haven't measured it but it seems that the Z calibration needs adjusting though the X and Y seem to be about right.  With motor drive, friction is not sufficient to hold the Z adjuster wheels when the carriage is being lowered so clamping is needed as I suspected.

Added simple clamping and been testing the Z motor drive.  If I set the speed high the very slight deviation from perfectly straight means that the rods suffer from centrifugal force and when the carriage gets near high up the unsupported ends of the rods start splaying out and shaking the whole printer!  Maybe with 500mm rods this is not a problem but with metre long rods it seems I shall need to support them at both ends.  This is only a problem with fast movement - during printing operations the Z movement will only be small and there will not be time for vibrations to get going.

I think I'll print the bottom rod stabilisers in TPU to give a bit of flexibility in case the alignment isn't perfect.

Now printing TPU.

Wiring up and testing under way.  Corrected steps/mm setting for Z and that's right now.  X and Y homing correctly.

X and Y axes aren't right and I've realised that I haven't recalibrated since changing to timing belts.  Motor timing pulleys have 20 teeth and the belt is 2mm pitch so the belt will move 40mm per revolution.  Microsteps per revolution is 200x16 = 3200 so steps/mm = 3200/40 = 80.  That should be precise.

The rods are definitely slightly bent but there seems to be enough flex in them that they should be alright restrained to be straight.  Whether the rods will bend straight (oxymoron??) or the TPU flexible bearing blocks will move remains to be seen

Seems the XY carriage has to be very closely level with the bed for the grid compensation to work.  And Z probe height is also critical.

Now printing the last TPU rod stabiliser.

All rod stabilisers installed.  One is causing binding so I've loosened it off and it seems to be better.