Lead Screw of a Lathe with Nut as Screw Pair

Screw Pair:
A screw pair is a kinematic pair that consists of a screw and a nut. The screw rotates and moves longitudinally and the nut moves axially along the screw. The screw pair is widely used in machines and mechanisms because it can convert rotary motion into linear motion and vice versa with high precision and efficiency.

Lathe:
A lathe is a machine tool that rotates a workpiece on its axis to perform various operations such as cutting, drilling, facing, turning, and threading. The lathe consists of a bed, headstock, tailstock, tool post, and carriage. The carriage moves along the bed and holds the cutting tool.

Lead Screw:
The lead screw of a lathe is a long, threaded rod that runs parallel to the bed and is driven by the headstock. The lead screw has a precise pitch and is used to move the carriage and cutting tool along the bed to perform different operations on the workpiece. The lead screw is an essential part of the lathe and provides accurate and smooth motion.

Nut:
The nut of a lathe is a block or cylinder that has internal threads that match the pitch of the lead screw. The nut is attached to the carriage and moves along the lead screw as it rotates. The nut is used to transmit the motion of the lead screw to the carriage and holds it in place during the cutting operation.

Screw Pair of Lead Screw and Nut:
The lead screw and nut of a lathe form a screw pair as described earlier. The lead screw rotates and moves longitudinally, while the nut moves axially along the screw. The screw pair of the lead screw and nut is responsible for accurate and smooth motion of the carriage and cutting tool along the bed. The screw pair provides high precision and efficiency in converting rotary motion into linear motion and vice versa.

Therefore, the correct answer to the question is option 'B' as the lead screw of a lathe with nut is a screw pair.