How Does a House Door Lock Work?
Key Locks Most house doors are unlocked with a key. Without the right key, the lock won’t open. Inside a lock is a cylinder, which runs through the doorknob and into the door. Inside the cylinder is something called a tang. When the door is locked, the tang sits partially inside and outside of the cylinder, which prevents the doorknob from being turned. When the tang is resting fully inside of the cylinder, the door is unlocked, and the doorknob can turn. Pins and Tumblers Cylinder locks contain on average five pairs of pins. Each pin has a different height. The pairs rest in shafts that start below the cylinder, go through the middle of the cylinder and above it. The upper shafts have tiny springs resting in the top of them. Normally, the lower pins rest in the bottom part of the shaft, and the upper pins sit halfway in the upper part and halfway in cylinder. This means the cylinder can’t rotate. When a key is inserted into the cylinder, the notches in the key line up with the pins an
