Found 800mm ones that would be adequate for my Giant printer though I was hoping for maybe 1m.  Estimated between Wed. 2 May. and Mon. 21 May.  Cost £30.72 plus £1 postage or for £20 extra I cab save a few weeks delivery time.  About £52 for expedited delivery.  Estimated between Wed. 25 Apr. and Wed. 2 May.

Yes - found 1m ones but at over twice the price of 800mm ones.  Much shorter delivery though.  Estimated between Thu. 26 Apr. and Fri. 27 Apr.   4 off for £64.44.  If I could strengthen the XY carriage I could get away with three of them but wonder if I could strengthen it enough...

EDIT - Latest delivery estimate is Tuesday 24th April.

Quickest delivery is for the 1m ones and they also fulfill my desires for the printer.  Using three instead of four saves £16 plus cost of other bits but leaves doubt about efficacy.  No, I think this ultimate printer needs the ultimate effort to get as near perfect results as humanly possible.  The funds for this project are coming out of the return I got from selling astro stuff so I'm just funding one project from another effectively.  I'm not sure where all this is going to end but I've already spent many hundreds on this printer though nothing like my astro projects!

If I buy 1m x 4 off and 500mm x 3 off (for my Titan printer), the total is £78.98 including a 5% discount for 2+ items.  With 3D printers and the things I make with them (eg. clocks and astro) being my No.1 interest, this is not out of the way

Ordered!

Now for the wait!!!  Twiddles thumbs" 

Plenty to get on with though   ooznest order of wider X rail and all those metal wheels due to arrive today   There's also the timing pulleys and bearings for the rods to see about.  Also, the proper power supplies and a few other things to attach to the frame.

Meanwhile, I can do some calculations.  Thread pitch 1mm so 1mm per revolution of the rods.  800 revs for full Z travel (if I stick with 800mm build height - could probably go a bit more).  Z steps/mm will depend on timing pulley ratio on the drive from the motor.  With 1:1 that would be 200steps/mm or 3200 microsteps/mm.

On 07/04/2018 at 16:48, Gina said:

Motors are all working.  Increased Z maximum speed to 3000mm/m = 50mm/s and it runs fine   A 100mm step taking just two seconds.  So a 700mm range is moved in 14s.  I checked the calibration with steel rule and it's correct within the tolerance of this method of measurement.  This movement seems easy even with motor current left at the default 800mA.

The steps per mm are currently 764 giving 50mm/s Z speed so if I just swapped to threaded rods and 1:1 pulley ratio the speed would be 764x50/3200 = 11.9mm/s.  A full Z travel of 800mm would take 800/11.9 = 67s.  I think that would be acceptable - about a quarter of the current speed which is super fast!!

Ordered 60t pulleys from Amazon - due to arrive tomorrow.  Now need to find closed loop belts of something like 1400mm length or more.  Longest found so far are these - POWGE GT2 Timing Belt L=1140mm W6=6mm 570 Teeth Color Black Pack in Closed Loop Of 10pcs  on a slow boat from china!!

@tekkydave Could you tell me where you got the long timing belt you used for the Z drive on your D-Bot printer, please?

I got it from Makers Hut on ebay they have GT2 6mm up to 1524mm. I used a 1350mm for mine.

Found this :-  GT2 2mm Timing Belt 1164mm x 6mm (582 teeth)

9 minutes ago, tekkydave said:

I got it from Makers Hut on ebay they have GT2 6mm up to 1524mm. I used a 1350mm for mine.

That's great Dave - thanks very much

Two 1524mm belts ordered   They should do fine.  Here's the arrangement I have in mind.  Two pulleys on the motor.

Timing belt clamping areas added to X carriage.

I thought I might have received the ooznest order by now but it isn't even out for delivery!    Guess there's still time for Parcel Force to deliver today as promised but I hate the waiting!

It's my guess that my order is not coming today!!!  So I'm playing "marble machines" instead

I was right it didn't arrive!

Arrived yesterday and I was then able to adjust the designs for X and Y carriages and start production.  Today production of parts is still proceeding.

Practically produced all the parts needed now at least for the new XY system.  Waiting for some extra hardware I've ordered to complete that.  Found I was missing some bits needed to mount the wheels.  They should arrive around this coming weekend, maybe Saturday.  The Z drive system will use trapezoidal threaded rod and that is not due to arrive until the following weekend.  I doubt it will be worth any trial print runs before the printer full upgrade is finished.

The Y carriages now seem correct but there are errors with the X carriage design which I missed.

Now have the extra hardware for mounting the wheels and carriages and been assembling them.  Also, stripped the old Z drive parts from the frame ready for the new system.  Now have the belts and most of the pulleys and can work out the positions.

Finished assembling the Y carriages but yet to thread the timing belts - needs the X carriage assembly finished first to attach the ends of the belts.  The Y carriage wheels are a bit tight ATM but I'm expecting that to relieve a bit as the PETG plastic creeps.  I'm using eccentric spacers so that it can be tightened when they get loose.  I need to reprint the X carriage main plate as there were a couple of small adjustments needed.

I was able to thread one of the belts to check the run for any problems and found the belt was touching the wheel mountings of the Y carriage so the Y carriages also need an adjustment in the design.  Can't print any more until I get my next order of PETG filament on Monday but can have the updated design ready.  This is the first CoreXY design I've worked on using timing belts and pulleys - been using braided cord in the past but that is not suitable for this monster machine.