The purpose of this research is to develop a dynamometer to measure the cutting force in the lathe process of brittle rock material. The dynamometer will measure the cutting force, feed force and axial force using a strain gauge sensor. The process design steps include: manufacture of dynamometers, manufacture of electronic circuits, process calibration and testing on brittle materials of rock. The calibration of the dynamometer is carried out with a universal testing bending machine and a universal dividing head clamping device to adjust the dynamometer in horizontal and vertical positions with the load increasing from 0 to 20 kg. The dimensions of the dynamometer are 190 mm x 40 mm x 40 mm and can measure cutting force, feeding force and axial force simultaneously. From the results of the dynamometer calibration, R2 is obtained for the cutting force of 98.7%, R2 for the axial force of 85.1% and R2 for the feeding force of 82.6% while in the cutting force of the rock material it is obtained: the maximum cutting force of 80.6 N, the maximum axial force of 5.1 N and maximum feeding force of 11.9 N.