Hello to everyone:
After building my own CNC for wood/aluminium I would want to make a new gantry CNC for steel and have found some troubles with spindles. I would really want to keep on a budget by now (thinking on upgrading later) so I'm trying to figure out what kind of spindle should I use, belt driven one with an electric motor? Direct driven with a stepper motor or with an electric one?
Also, as I'm going to process long pieces (that's why I have chosen gantry) but not too deep removal - just 3.5*mm in the deepest part - I don't need it to be very aggressive in deepness in exchange for saving money. So what kind of torque/power would I need?

Thanks to all and sorry about my bad English