Well, that waterblock was alright for a while but the slightest movement caused the O rings to leak.  After a while they would settle down and seal again.  Trouble was, it took very little to cause a leak again so I've abandoned that and made a waterblock from aluminium.

Here is a drawing of the waterblock in clear blue to show the inside features plus two photos.  The brass parts are for attaching the water tubes and the top bit fits the E3D Titan Extruder.  The larger M6 threaded part, bottom right, takes the heatbreak.

Now to the heaterblock.  The one shown above, 30mm high with two 60W heaters and a straight filament path worked alright but printing speed with a 2mm nozzle was limited to around 30mm/s.  I wanted to print faster than this so Chriske and I did some "out of the box" thinking.  It was his idea to try a folded filament path to provide a much longer melting distance.  This would depend on whether the filament would be soft enough to turn a right-angle after just 20mm or so.  I decided to make this type of heaterblock and see if it worked.  First attempt was with one heater to test the principle - it worked but the heater was unable to provide enough heat to melt the filament at the speed the extruder was capable of, so I made a second with two heaters.  That has proved to work well and the maximum printing speed has increased to 90mm/s - three times the previous best.

Explaining a 3D object in a 2D medium isn't easy so I've taken three screenshots of the 3D drawing which I'm hoping will help to explain the construction.  The first screenshot is a top view, showing the holes for the heaters each side near the top of the image.  Very top are holes for the clamping screws, with a threaded part and clearance on top.  Between the two heaters is the M6 threaded hole for the heatbreak.  A hole nearly to the bottom of the block takes the filament down to a horizontal hole.  This takes softened filament to the front of the block where a vertical hole takes it up to the top again (well almost).  Here another horizontal hole takes the filament to the bottom left of the image (actually top left of block), connecting with another vertical hole taking the filament down again and ending in another M6 threaded hole to take the nozzle.  M5 grub screws are used to seal the open ends of the holes where filament must not come out.

Glued very thin bits of aluminium sheet onto the left hand end to seal the ends of the horizontal holes and now tested the waterblock under full pumped water pressure and there are no leaks - not even the slightest dampness.  The grub screws and pipe connectors were sealed with silicone sealant (as used for baths and other bathroom fittings and windows etc.).

This photo shows how the waterblock is held in the extruder casing - the front has lugs which hold the neck piece firmly in position.

Printing a test block in PLA - 100mm x 100mm x 10mm.  This is first layer and half of second printing pretty much perfectly. 

Photo of latest X carriage.

I'm currently almost rebuilding this printer as I'm dissatisfied with certain aspects of it.

1. The Z drive with the 4 threaded rods is very noisy and slow.
2. The brackets for the bed failed to hold it when printing with a high bed temperature so I had it supported on pieces of wood on the floor.
3. In spite of the bungy cords to lift it, the umbilical tended to catch at high level printing.
4. The arrangement of Z drive and XY carriage limited the printing area.

To overcome these problems I'm changing from moving the XY plane for Z axis to the more standard moving print bed, replacing the 5mm thick aluminium bed with a 2mm aluminium sheet supported on aluminium extrusion, parts of which will form the Z carriage.

The threaded rod Z drive will be replaced with cord support on the four corners as I have in one of my other printers. The cords will be taken over pulleys to a crosswise bar on which they will be wound up to lift the bed, with the bar driven by reduction spur gears (3D printed) from a stepper motor.

Finished the stripping down and now re-building.  Y rails sorted out and in place.  Y carriages (with X rail) run very smoothly.  Also, have XY motors attached with brackets.

Rear pulley blocks designed and printed in ABS and checked for fit.  Final blocks will be printed in PETG.

Now working on the Z drive.  A horizontal aluminium tube, 1" (25.4mm) OD will go across the top from side to side and centred front to back.  This will be driven by a pair of spur gears from a NEMA17 stepper motor.  Cords from the corners of the bed will go up over pulleys and be wound up on the tube.  There will be approximately 9 turns to raise the bed from bottom (Z = 700mm) to top (Z = 0).  With a cord diameter of 0.4mm these turns will take up just under 4mm for each cord.  Approximate bed levelling will be achieved with guitar pegs attached to the bed frame - accurate bed levelling will rely on the auto-bed-level-compensation of the controller electronics.

Calculate the Z drive parameters :-

1. Shaft diameter = 25.4 mm giving circumference of 25.4 x π = 79.8mm.
2. Motor does 200 x 16 = 3200 µsteps per revolution.
3. µsteps/mm therefore = 3200 x 10 / 79.8 = 401.02.

401 µsteps/mm seems pretty reasonable.  That's if I've got the calculation right ?

Looking at This Cable Chain.  Think I'll design my own...

Printing blocks for the corners of the Z carriage/bed.  These have three functions :-

1. Hold the Z carriage frame members together, square and level.
2. Hold the wheels that hold the bed in the right position horizontally.
3. Provide brackets for the bed level adjusters (guitar pegs).

Bed corner blocks completed and installed plus all four suspension cords connected to the adjusters.  Z drive pinion printed, pushed onto motor shaft and motor mounted on main printer frame.  On testing by hand it was found that the Z carriage frame collided with the left hand XY motor so a new motor mounting was required.  Since the standard NEMA17 bracket wouldn't fit, a 3D printed motor bracket was designed and printed in PETG.   With all drive mechanics completed, the printing capacity was measured - 470mm x 490mm x 650mm (XYZ).

Still to do :-

1. Decide location and mount control box and hotend cooling water reservoir.
2. Wiring and water tubing.
3. Umbilical support cable chain.
4. Filament reel support.

Think I'll start a new blog as the upgrade make this printer quite different.  GinaRep Giant Mk.3.