Millwright Level 1 Practice Exam 2025 - Free Millwright Practice Questions and Study Guide

The feed rate on a milling machine is primarily controlled by the gearbox found in the knee of the milling machine. The gearbox is designed to provide different gear ratios, which allows operators to adjust the rotation speed of the lead screw or feed screw connected to the machine's table and cutting tool. By selecting various gear settings within the gearbox, the operator can effectively modify how quickly the workpiece moves relative to the cutting tool, thereby controlling the feed rate.

In contrast, while other options may have roles in certain types of milling machines or specific operations, they do not directly control the feed rate in the same fundamental way as the gearbox. Servo motors may contribute to automation and precision in more advanced systems, but the mechanical and manual methods used in traditional milling setups rely significantly on the gearing system within the knee for feed rate adjustments. Manual cranks allow for direct operator control over movement, typically for precise adjustments rather than sustained feed rate control. Hydraulic systems can facilitate movement as well, but in the context of standard feed rate control, they are less common than the gearbox mechanism.