i am building a cnc mill to cut some steel but most aluminum and wood .what size on stepper motors would be best for this job.has anyone ever bought a cnc kit from stepper world /do they ship to canada /.anyways i was thinking about 190 oz motors
thanks

That is a BIG discussion. Off the top of my head, you need to consider these things when selecting a stepper motor:
-table inertia (and desired acceleration/deceleration)
-cutting speed
-rapid speeds
-cutting forces
-how much torque does the stepper generate at whatever feed/rapid
-current required (controller)
-microstepping?
-leadscrew efficiency
-leadscrew pitch
-table resolution per step/microstep

...there are probably some others that I forgot. I would say that 190 oz*in is not enough torque...but you really need to be concerned with torque AT SPEED...everyone rates stepper motors at stall speed (zero rpm), which isn't really practical.

I suggest 34 frame steppers as opposed to 23 frame steppers. You will be able to find much higher performance 34 frame steppers for a lot less than 23 frame steppers.

Good luck,
Justin

do you know were i could buy any good cheap kits for my application online

http://www.xylotex.com/4AxSysKit.htm seems to be a decent kit, and the motors are a good size.