My steel framed router

[Jonathan]

I'm thinking of ACME (multi-start) instead of ball screw and aluminium (tube) for frame

Why aluminium tube? Surely steel is easier to join (by welding) and stronger for the money...

3-axis upgradeable to removable 4th-axis (rotary)
I'll order the steppers kit soon
this is the link
http://cgi.ebay.com/4-Axis-Nema-23-S...item4155c86bd7

I think you'll find that kit to be of limited value. The stepper motors have an extremely high inductance (18mH), which combined with the low voltage that driver runs on will really limit your motor speed.

[F.O.X]

Thanx for your replay Jonathan,,
The fixed work table from steel but the gantry is movable and steel's density is 7850 Kg/cu.m compared to AL 2650 Kg/cu.m .
it's easier for me to use steel for all the body but I'm not sure if the 2N.m motors can handle it ,I didn't finish my calculations


about the kit,, I'll consult my friend ,an elec.eng. , I hope it can be tuned.
I'm short of time and money and the drivers are more expensive than the board , I can switch later to better drivers
Right now I'm in big trouble , I can't find screw lead (ACME) and slid rails in the market , that's why I didn't finish calculations , my last hope is printers' scrap .

Does anybody knows website? with international shipping? or another way? :S