What Rekeying Actually Means
Rekeying means changing the pin configuration inside a lock cylinder so a new key operates it and the old key no longer works. The existing hardware — deadbolt, knob, lever — stays on your door. Only the internal pins are swapped out.
Most pin-tumbler locks have five or six spring-loaded pins inside the plug. Each pin is actually two pieces: a key pin (bottom) and a driver pin (top). When you insert the correct key, the gaps between each key-driver pair line up exactly at the shear line, allowing the plug to rotate and the lock to open.
A locksmith removes the plug, dumps out the old pins, and inserts new ones that match the cuts on your new key. The entire process typically takes five to ten minutes per lock once the locksmith has the cylinder out.
When Rekeying Makes Sense
Rekey when you want to keep your existing hardware but need different keys. Common scenarios:
- You just moved in. Previous owners, tenants, contractors, and cleaners may have copies of the old key.
- You lost a key. If you don't know where it is, anyone who finds it can access your home.
- A roommate or relationship ended. You gave someone a key and want it back without collecting physical copies.
- You want one key for all locks. Instead of juggling separate keys for front, back, and garage, a locksmith can rekey everything to match.
Rekeying costs less than replacing the entire lockset and is faster. If your locks are in good condition — no rust, smooth operation, ANSI Grade 2 or better — rekeying is usually the best move. Replace only if the lock is damaged, low-grade, or you want to upgrade security features like a smart lock or reinforced strike plate.
Inside a Pin-Tumbler Lock: The Basics
Most residential deadbolts and knob locks use pin-tumbler cylinders. Here's the anatomy:
- Plug: The rotating part the key slides into.
- Pin chambers: Vertical shafts drilled through the cylinder body and into the plug.
- Key pins: Sit on top of the key blade; different lengths match the key's cuts.
- Driver pins: Rest on top of the key pins, pushed down by springs.
- Shear line: The boundary between plug and cylinder body. When all pin pairs split exactly at this line, the plug can turn.
Insert the wrong key and the driver pins block rotation. Insert the correct key and each pin stack lifts to the perfect height, freeing the plug. Rekeying swaps the key pins so a different key becomes the correct one.
Wafer locks — common in filing cabinets and some older car doors — work similarly but use flat wafers instead of pin stacks. They can also be rekeyed, though the process differs slightly.
The Rekeying Process Step-by-Step
Here's what a locksmith does when rekeying your deadbolt or knob:
1. Remove the lock. Unscrew the interior trim, pull the cylinder from the door. Some locks have a small retaining pin or clip; poke it with a pick tool, turn the plug slightly, and the cylinder slides out.
2. Remove the plug. Insert the current working key (or use a plug follower if no key is available) and turn the plug to align the pins. Tap out the retaining clip at the back of the cylinder, then push the plug out carefully so springs and pins don't fly everywhere.
3. Dump the old pins. With the plug removed, the old key pins drop out. The locksmith sets them aside — they may reuse common sizes for other jobs.
4. Insert new pins. The locksmith inserts key pins that match the new key's cut depths. Each position gets a pin of the correct length so the shear line aligns when the new key is fully inserted.
5. Reassemble. Slide the plug back into the cylinder using a plug follower to keep the driver pins and springs in place. Reinstall the retaining clip, test the new key, and mount the lock back on the door.
Total time: about five minutes per lock. A locksmith can rekey your front door, back door, and garage entry in under half an hour if the locks are standard pin-tumbler models.
Rekey vs Replace: Which Should You Choose?
Rekeying is faster and cheaper. Replacing gives you a fresh start with new hardware. Here's the breakdown:
Choose rekeying if:
- Your locks are already ANSI Grade 1 or Grade 2 (solid brass or steel, smooth operation).
- You just need new keys — no interest in smart locks, keyless entry, or upgraded strike plates.
- Your deadbolt has at least a one-inch throw and a hardened steel bolt.
- Finish and style match your door hardware and you're happy with the look.
Choose replacement if:
- The lock is sticky, corroded, or the bolt doesn't fully extend.
- You have a builder-grade lockset (often brass-plated pot metal, ANSI Grade 3 or unrated).
- You want to upgrade to a smart lock with Bluetooth, Z-Wave, or Wi-Fi connectivity.
- The strike plate screws are short (less than three inches) and you want to add a reinforced plate with screws into the wall stud.
- You're consolidating to a single key brand across multiple properties and your current locks are off-brand or discontinued.
If you're unsure, a mobile locksmith can inspect your locks on-site and recommend the most cost-effective option. For more details on our residential services, visit our services page.
Master Keying and Keying Alike
Rekeying also lets you set up master key systems or key-alike configurations.
Keying alike: All your locks use the same key. One key opens your front door, back door, deadbolt, and garage side-entry. Convenient for homeowners who don't want a heavy keyring.
Master keying: Each lock has its own change key, but a master key opens all of them. Common in rental properties (landlord keeps the master, tenants get individual keys) or offices (manager has master access, employees open only their own doors).
Master keying requires an extra pin in each chamber, creating two shear lines. It's slightly less secure than a single-key system because there are more valid key combinations, but the convenience often outweighs the risk in controlled environments. A locksmith can set up a master/sub-master system during the rekeying process without replacing hardware.
Can You Rekey a Lock Yourself?
Technically, yes — rekey kits are available at hardware stores for common brands like Kwikset and Schlage. The kit includes new pins, a plug follower, tweezers, and instructions.
Realistically, most homeowners find it fiddly and time-consuming. If you drop a spring or pin, you're crawling on the floor with a flashlight. If you insert the wrong pin size, the key won't turn and you have to start over. And if you damage the cylinder or lose a critical part, you've turned a $20 rekey into a $150 lock replacement.
A mobile locksmith has the tools, experience, and replacement parts on hand. They rekey faster, guarantee the work, and can handle tricky situations like frozen plugs or worn keyways. For the cost difference — usually $15 to $30 per lock — most people prefer a professional visit. Plus, if you're rekeying after a break-in or lockout, you probably want it done immediately and correctly.
For more locksmith tips and guides, check out our blog.