Stepper size recomendation.....

Hello Group,

I need a size recomendation for stepper motors. I have built a CNC
router and it is running well with 160 oz./in. motors.

My next machine/conversion is a small metal cutting lathe. This
lathe has a working range of approximately 5" cutting diameter and
the spindle drive motor is only about 1 HP. If you are familiar
with the common reference to "9 x 20 Chinese lathes", this is the
machine I am converting to CNC.

The machine itself isn't capable of heaving roughing, but I wouldn't
want to cut back on any capabilities. So I am trying to determine
the best size motors (in oz./in) I should be looking for. My "More
power" side of me wants to bolt on some 600 oz/in motors, but my
wallet says nema 17s ;-)

THanks for any advice!