Hi,
I am building a CNC, in the style of an I3. What I need help with is the drive of the Y axis.
I intend to use a belt drive, what I am puzzling with is whether to use a single belt or two.
There is not a lot of weight involved, the bed is 380 X 280 X 5 mm aluminium, not really a lot more that a printer bed with base, heat bed, and glass.
Any help on this will be highly appreciated. Thanks

The I3 design is really not a good idea for a cnc platform

see something like The Mostly Printed CNC (MPCNC) [www.v1engineering.com]

wider/ more belts would be better. The machine needs enough strength in the belts to move it through the material being machined.

Thanks Dust had an idea that that would be the correct way to go.
You say wider belts can you give me an idea on them.
Thanks for the link, interesting, I will have a closer look at that.

OK, have taken Dust's advise and gone with two Nema23 steppers and 10mm wide belts.

OK, had second thoughts on the drive system, and have elected to go with threaded rods, so now I have 5 nema23 steppers and 6500 driver modules, the big problem I have is my controller has only four axis, am I still able to double up on the zed axis, as we do with the printer, Thanks