To determine the cuttability of rock, it is important to know the amount of force applied to the blade edge at its contact with the rock and the volume of the cutting debris. These forces can be estimated using analytical methods and laboratory rock-cutting tests. In this paper, by performing linear cutting tests on four rock samples with weak to medium strength using a chisel blade, the maximum, and average cutting forces applied to the blade during rock cutting were measured and compared with the values ​​calculated from the Evans theoretical method. The results showed that with increasing cutting depth, all three maximum, average, and Evans cutting forces increase linearly, and at a given cutting depth, the Evans' cutting force is usually less than the maximum cutting force and greater than the average cutting force obtained from the linear cutting test. Also, the ratio of maximum shear force to average shear force has a direct relationship with increasing cutting depth and should be considered in the design of the drilling machine, so that its value is between 1.16 and 1.49 for a cutting depth of 1 mm and close to 1.7 for a cutting depth of 4 mm. The results also showed that this ratio increases with increasing rock brittleness, and the lowest value of this ratio is related to salt with a brittleness of 4.82 and the highest value is related to coal with a brittleness of 11.86.