Hi All,

After lurking for a while, this is my first real-post.

I'm designing a gantry mill with a 2000mm x 1700mm x 900mm of work envelope. I'm not a CNC machinist but am hoping to learn from this experience and from your wisdom. What an excellent site!!!

The machine frame (under design) is currently in 120mmx80mm-8mm thick rectangular CRS tubes, welded and stress relieved. The stress relieving part still needs to be taken care off. The base frame is 2500mmx2000mmx400mm.

The gantry is also in the same section CRS frame as the base.

The Z axis is built out of a 220mmx220mm-8mm thick CRS tube and welded to a 120mmx80mm CRS tube.

All the axis have linear rails with 2 carriages each. The design is not yet totally done. I'm in the process of ordering the rails+carriages and precision ground (C5 grade is all I can afford) ball screws. The two makes of ballscrews and rails that fall in my budget are:

www.hiwin.com lead time 5-6months by a local supplier
www.comtop.com.tw lead time 3-4months by a local supplier

I'm looking for advice from someone who has seen/tried/has-experience with these products from them as far as rails+carriages and ballscrews+nuts go.

Please respond.
thanks
N