The industrial sector already knows that in a tightly meshed counter-rotating twin-screw extruder, a large separation force is generated in the calender gap, pushing the Screw Barrel toward the barrel wall. The result is severe wear in the area defined at 30° and 60° angles to the vertical. In this study, the pressure around the barrel was measured when two hard PVC resins were extruded in a laboratory extruder with a diameter of 55 mm, and the force on the screw core was determined. Numerical flow simulations were also carried out using the power-law viscosity parameters of the resin. It is determined from the experimental results that the resultant force is in the direction of an angle of 30 degrees. From the computer simulation, the angle is between 18° and 25°. Some people think that due to the additional contribution of gravity, the resultant angle in a large-diameter extruder will be slightly larger.