What is the purpose of the leadscrew in a lathe?

The leadscrew in a lathe plays a crucial role in coordinating the movements of the carriage and the workpiece. Its primary function is to enable the precise linear movement of the carriage along the bed of the lathe, which is essential for operations like turning and threading.

When the leadscrew rotates, it translates that motion into linear movement for the carriage, allowing the cutting tool to engage with the workpiece accurately. This synchronization ensures that the cutting tool can be advanced and retracted safely and effectively during machining processes.

In contrast, the other options do not accurately represent the leadscrew's function. Supporting the spindle focuses more on the structural aspects of the lathe, controlling workpiece movement pertains more to the workholding mechanisms, and rotating the cutting tool relates to the spindle's role rather than the leadscrew's. Understanding the leadscrew's purpose aids in comprehending how different components of a lathe work together to achieve desired machining results.