Oklahoma Locksmith Practice Exam

Which part of a key cylinder interacts directly with the locking mechanism?

1. Shell

2. Tumbler

3. Pin

4. Spring

The correct answer is: Pin

The pin is the component of a key cylinder that interacts directly with the locking mechanism. In a typical pin tumbler lock, the key is designed to fit into the key cylinder and raise the pins to specific heights. When the correct key is inserted, the pins align at the shear line, allowing the cylinder to rotate and operate the locking mechanism. The function of the pins is essential for the locking process because they prevent the cylinder from turning unless the correct key is used to align them properly. When the incorrect key is inserted, the pins will not align correctly, thereby keeping the lock in a locked position and securing whatever the lock is protecting. Other components, such as the shell, tumbler, and spring, do play important roles in the overall function of a lock system; however, they do not interact directly with the locking mechanism in the manner that pins do. The shell provides the outer structure, the tumbler typically refers to part of the locking mechanism that may assist in the overall operation, and springs are used to provide tension to the pins, but it is the pins that are crucial for the interface of the key with the locking mechanism.