An Acme screw thread is a type of trapezoidal screw thread with a 29-degree thread angle, which is commonly used for power transmission applications such as lead screws and jackscrews. The thread profile of an Acme screw thread is trapezoidal in shape, with a flat top and bottom and sloping sides. This design allows for high efficiency and greater load capacity compared to other thread forms. Acme screw threads can be made in various materials, including steel, brass, and plastic, and are available in a range of sizes and pitches to suit different applications.