Red Seal Machinist Practice Exam

What function does a lead screw serve in a lathe?

1. It holds the workpiece in place

2. It facilitates precise movement of the carriage

3. It controls the speed of the spindle

4. It adjusts the tension of the tool holder

The correct answer is: It facilitates precise movement of the carriage

The lead screw in a lathe plays a crucial role in enabling precise movement of the carriage. It converts the rotational motion of the screw into linear movement, which allows the carriage to travel accurately along the length of the workpiece. This precise control is essential for operations such as threading, where exact measurements are vital for achieving the desired specifications. The design of the lead screw ensures that as it turns, it moves the carriage consistently in small increments. This mechanism is particularly important when conducting operations that require high levels of accuracy, such as cutting threads, grooves, or intricate profiles. The lead screw allows machinists to set exact distances for the carriage to move, ensuring that cuts are uniform and the workpiece maintains its intended dimensions. In contrast, other components or functions mentioned in the list do not accurately represent the role of the lead screw. For instance, holding the workpiece in place is typically the job of a chuck or a vise rather than the lead screw. The control of spindle speed is managed by the lathe's drive mechanisms, separate from the lead screw's function. Adjusting the tension of the tool holder relates to securing the cutting tool in place, which does not involve the lead screw at all. Thus, the lead screw's primary purpose