North Carolina Locksmith Practice Exam

What is "Root Depth" in the context of key cutting?

1. The deepest point of a key's cut

2. The dimension from the bottom of a cut to the bottom of the blade

3. The total length of a key

4. The thickness of the key at its lowest point

The correct answer is: The dimension from the bottom of a cut to the bottom of the blade

Root depth refers to the measurement that indicates the vertical distance from the bottom of a cut in a key to the bottom of the key blade. This measurement is crucial for ensuring that the key will fit properly into the lock and function as intended. When a locksmith is making a key, understanding root depth is essential to match the key cuts accurately with the pins in the lock, allowing for smooth operation. In this context, knowing root depth helps ensure that the cuts made on a key align correctly with the pin tumbler mechanism of a lock. If the root depth is not accurate, the key may not operate smoothly or could even damage the lock over time. Other dimensions, such as the total length of the key, the thickness at the lowest point, or the deepest point of a cut, do not provide the necessary information to ensure proper operation and fit in the context of key cutting. Understanding root depth specifically focuses on the relationship between the cut depths necessary for that key to function correctly in its intended lock.