The type of screw shaft configuration which is represented in Figure 3.2 is commonly used in screw presses, because the manufacturing process is easy. In Komet Oil Presses, this type of screw shaft configuration is used[36]. The pitch and the root diameter are constant through the screw shaft. The rate of pressure increase in this type of a screw press is analogues to the rate of pressure increase in hydraulic presses. In both of them, pressure increases linearly. However, seed flow in the screw press is continuous whereas the compressed seeds must be replaced after each stroke in a hydraulic press.