What Home Rekeying Actually Does to Your Locks
Rekeying is a mechanical process that changes the key-bitting of an existing lock cylinder without replacing the entire lock body. Inside every pin-tumbler cylinder — whether it is a Schlage deadbolt, a Kwikset door knob lock, or a heavy-duty mortise lock — there are a series of spring-loaded pin stacks. Each stack has a key pin and a driver pin. The key you own pushes the key pins to precise heights so that the shear line is clear and the cylinder can rotate. When a technician rekeys the lock, they remove those key pins and substitute a new set matched to a completely different bitting pattern. The result: the old key contacts the wrong pin heights, the shear line stays blocked, and the cylinder refuses to turn. Your new key is the only one that works.
This is meaningfully different from changing locks, where the entire lockset is uninstalled and a brand-new one takes its place. Rekeying preserves your existing hardware — handy when you have a high-quality mortise lock installed in an older Country Club Hills home and would rather not spend money on a full replacement. It is also why rekeying is so commonly requested after move-ins, break-ups, completed renovation projects, or any event that transferred key copies to people who no longer need access.