Steel Gantry Machine 1500x750x200

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This story is about Steel Gantry Machine with work-area 1500x750x200 for aluminium and wood.
First I was going for a fixed gantry machine but bigger work-area changed my mind. As long as I have to purchase expensive components the price difference for longer components is not so dramatic - but it gives nice advantage.



Main frame welded steel 80x80x4mm.
Steel gantry consist of 2 pcs 100x100x3mm tubes welded together and some 8mm steel plates.
Z assembly is mostly 25mm aluminium with 2,2kw watercooled spindle.
Ballscrews X,Y=1610; Z=1605.
HIWIN 20mm rails all axes. Epoxy leveled.
Please feel free to comment my design. In case of positive feedback then next step would be to order rails and ballscrews. Measure them and then finalize design and start the build.

I have couple of questions for more experienced guys:

1. Can I use L (0,375" = 9,525mm) pitch pulleys with a 12,7mm wide belt from steppermotor to ballscrew? I can get those pulley for free. Together with 240L belt. But this belt is too long and pulley centre hole is 10mm, whish I cant use on Nema 23 anyway. So I have to buy half the pulleys and belts. May as well buy proper with belts and pulleys all around?
2. What ballscrew machining are you using when belt pulley will be attached?
3. Hole gantry with Z and everything will be close to 80 kg. Can I put my money on 2x Nema 23 3,1Nm together with a decent 70Vdc PSU?
4. What HIWIN blocks do most of you prefer: HGH or HGW? Sure it depends from design but I think I will go with HGH20CA from BST Automation.

Tanks for reading!