Hi what is the maximun weight of a gantry that a Nema 34 651 oz can carry ?

The holding torque of the NEMA34 motor is rated at 651 oz-in. This is the maximum amount of weight the motor holds in a stationary position while optimal current is being applied through the driver. This is equivalent to 40.68 lbs per inch. Torque is measured from the center of the shaft. The torque applied to the shaft moving 1 inch is inversely proportional. For example: Moving 1/2" on the shaft has a maximum of 1302 oz or moving 2" has a maximum of 325.5 oz.