G Machine is used to obtain rpm ratios and spur gears system efficiency, reviewing the spur gears dynamic and inertial momentum in each shaft and its accessories. The acceleration and angular velocity of each gear row is calculated by means of angle sensor. Angle meter sensor is of optocoupler type located in four corners of machine; as a result, they reports the time at each 90° rotation of gears with high accuracy on the digital display. Machine’s gear system consists of four shafts; when these shafts are engaged, various ratios of velocity and output torque are obtained. The gears are manufactured by Hobbing technology, which is one of the best methods for making Involute curve for the selected gears. Bearings have self-aligning couplings for centering the shaft with bearing to reduce errors in calculation and efficiency. Moreover, collars with certain radii are coupled to each shaft ensuring the calculation of friction and output efficiency generated by engaged gears through fastening hanger and placing precise weights enabling the operator to compare the results with the existing theories.