Correct option is D
The lead screw is used to move the carriage automatically during threading operations on a lathe machine. It is specifically designed for precision movement of the carriage, ensuring accurate thread cutting. The lead screw is engaged with the carriage through a half-nut mechanism, which allows for controlled movement synchronized with the spindle rotation, enabling the creation of threads on the workpiece.
The bed is the base of the lathe machine on which all other parts (like the carriage, tailstock, and headstock) are mounted. It provides support but does not move the carriage during threading.
The hand wheel is used manually to move the carriage or tool post during general operations. It is primarily used in operations like turning, facing, or adjusting the tool.
The feed rod is used to provide power to the carriage for operations like turning or feeding the tool during non-threading tasks. However, it does not directly control the automatic movement during threading. The feed rod supplies the power, but the
lead screw actually moves the carriage during the threading process.
