Hi,
I've built a 10'x5' with china steppers from Long motor corp.
3 1/2"x 2 steel tube, 3/4" plywood, 3/4 MDF top. Home drilled 3/4" round stock linear rails. The newer style plastic bearings. Nema 34 stepper motors Probotix USB-CNC and software .Worked so,so.
With all my errors in design, and rebuilds spent $3600.00
i now have 12 mm supported rails on order from china. It will be a lot faster.

Just started cutting new metal for a 28"x39" machine aluminum box tube,
16 mm linear rails, ball screws, and nema 23 stepper motors with Usb-cnc card and software, about $1100.00 cost.