I am facing some issues regarding a stepper motor drive. The stepper motor I have is a 20KG 12V DC L/R Full step driven one. I need it to drive a Lead screw which eventually builds up pressures of the likes of 400Kg cm in a cylinder. I have attached a gear box of ratio 12:1 to the stepper and tried boosting the torque. With the direct coupling the pressure used to reach around 100-150 Kg cm but even with the gearbox which I presume would boost the torque by a factor of 12 the pressure fails to rise above 200. And the stepper slips if I try to run it at high RPMs (15RPM ) even without any load. What can I do to find a solution to these 2 problems? What could be going wrong in this whole exercise? Thanking you in anticipation. Regards, Chetan.