Vertical fixed gantry. Design & build. (Steel/epoxy)

[JAZZCNC]

Oh before I forget your not from Yorkshire are you.? My best mate at school was called Paul Green but he moved away.!

I am definitely thinking about one motor for both screws. It seems both the simplest and best way of syncing the screws.
The gap between the screws is ~1770mm. Is this something to worry about with belts?

No except you'll have to have it made for you, it won't be something you find on the shelf. Most decent bearing/belt suppliers will get you one made. If at the time you have trouble drop me an email and I'll put you intouch with someone who will.

Is it possible/feasable to have a central motor driving two pulley wheels (one for each screw) so each belt is half the length.(each belt would need a tensioner)
quick & dirty sketchup

Yes and infact my first effort with belts was done something like that but in a V shape.