PMMI Mechanical Practice Test 2026 - Free Mechanical Practice Questions and Study Guide

A set screw is used in a hub to securely hold a key in the keyway, providing essential guidance for the transmission of torque between a rotating element, like a shaft, and a stationary one, such as a hub or pulley. The set screw is typically tightened against the key or the shaft, ensuring that the key remains firmly in place and preventing any unwanted movement or slippage during operation.

This secure fit is crucial for maintaining the integrity of the system, as any movement might lead to misalignment, decreased efficiency, or potential damage to the components involved. By using a set screw, you take advantage of a design that allows for easy adjustment and maintenance while ensuring strong engagement with the key, making it an effective choice for this application.