Associated Locksmiths of America (ALOA) Practice Test 2025 – Your Comprehensive All-in-One Guide to Exam Excellence!

The correct answer is the cam stop washer, as it plays a crucial role in determining the plug's rotation within a cam lock. This component is specifically designed to limit how far the plug can turn, effectively controlling its movement. When installed correctly, the cam stop washer will allow the plug to rotate only to a certain degree, ensuring that the lock operates as intended without over-rotation, which could lead to malfunctioning or failure of the locking mechanism.

The other components have different functions in the overall operation of the lock. The locking pin is involved in securing the plug in place but does not directly determine its rotation. The set screw typically secures the entire lock assembly and maintains its integrity rather than influencing plug movement. The backing plate provides support and structure to the lock but again does not affect the rotation of the plug itself. Understanding the role of the cam stop washer is essential for proper installation and functionality of a cam lock.