im using 3 HT23-400-8 400ozin Stepper Motors from
www.probotix.comand im using the driver that come with it which is 4 x ProboStep VX Uni-Polar Stepper Motor Driver
there is no gearing the ratio is 1 :1
i am also using half steps
x axis moves 15mm per 1x revelution of my screw
y axis moves 5mm pre 1x rev
z axis moves 3mm per rev