Lead screws and threaded rods are two common parts in the mechanical field. They have some differences in shape and purpose. The lead screw is a part with a threaded structure that is used to convert rotational motion into linear motion or force into torque. A lead screw usually consists of a larger diameter shaft and a threaded nut. When the screw rotates, the nut moves up and down along the screw axis, thereby achieving linear motion. Lead screws are widely used in various mechanical equipment, such as machine tools, lifting platforms, automatic doors, etc. The lead screw is also a part with a threaded structure, but unlike the lead screw, the screw is mainly used to fix or connect objects. A screw usually consists of an elongated shaft and a thread structure, which can be external or internal threads. Externally threaded screws can be used to secure two or more objects together, while internally threaded screws are usually used to connect screws or other parts. To sum up, the screw is mainly used to convert rotational motion into linear motion or force into torque, while the screw is mainly used to fix or connect objects. They differ in purpose and function, but share the characteristics of threads in shape and structure.