North Carolina Locksmith Practice Exam

The correct choice refers to the shoulder of a key. The shoulder is the part of the key that serves as a stop during the key insertion process into the lock. It is designed to prevent the key from being pushed too far into the lock mechanism, ensuring proper alignment for the tumblers or pins to engage when the correct key is used. This portion of the key allows for the correct positioning of the key within the lock and works in conjunction with other components to facilitate smooth operation.

In discussing the other terms, the heel typically refers to the end of the key opposite the tip and may not provide the same functional stopping capability as the shoulder in reference to key operation within a lock. The bow stop refers to a feature on the bow (the part of the key that is held) which may not always play a significant role in the key's insertion mechanics as compared to the shoulder. The top stop is not a commonly recognized term in locksmithing in the context of key projection stops, making the shoulder the most accurate and appropriate choice for defining a projection from a key that acts as a stop excluding the tip stop.