Key Duplication
Updated November 6, 2026
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Safety
Only allow a technician to duplicate keys for locks or vehicles the caller owns or is authorized to access. Reputable key duplication locksmith professionals may ask for proof of ownership or identification, especially for car keys made or transponder key duplication, since duplicated keys provide physical access to property. Avoid buying or using duplicated keys of unknown origin, and never ask a technician to bypass a lock instead of simply making a proper duplicate. If a key broke off inside a lock, stop attempting to extract it with improvised tools, as this can damage the cylinder and turn a simple key copying job into a full lock repair.
Before the visit
Before requesting key duplication, gather the original key if available, since copying from an original produces the most accurate result. Note the brand of the lock or vehicle, the year, make, and model for automobile keys made, and whether the key has a transponder chip, remote head, or laser-cut profile. Decide how many key duplicates are needed and where they will be stored. For car key duplication, have the vehicle available if programming is required, and locate the owner's manual or registration if proof of ownership may be requested. Clear the area around the lock or vehicle so the key cutter has room to work, and confirm whether an existing spare still works so the technician knows whether the issue is a worn key or a failing lock.
Repair vs replace
A technician should be called when a duplicated key does not turn smoothly in the lock, since the cut may need adjustment or the cylinder may need servicing. Schedule a visit when a transponder key duplicate fails to start the vehicle and needs reprogramming, or when a remote-head key copy stops locking and unlocking doors. If an original key is worn, bent, or cracked, a key maker can cut fresh car keys made or house keys from the lock's code rather than copying the wear. Call for help when a key snaps inside a lock and part remains stuck, when a high-security or restricted key requires specialized key cutters, or when all spares are lost and new keys must be originated from the lock itself.
When to replace
Full replacement is the better option when the original key is missing entirely and no duplicate car keys or house spares exist, requiring the key to be cut from the lock or vehicle VIN. Replace rather than copy when a vehicle's key and ignition have been rekeyed after a security concern, since old duplicates should no longer work. Consider replacement when a transponder chip is dead and the key cannot be reprogrammed, when a laser-cut or sidewinder key blank is worn beyond accurate copying, or when upgrading to a more secure lock system that requires an entirely new set of keys made. Replacement is also appropriate when a landlord, homeowner, or vehicle owner wants all old keys invalidated after a move, lost set, or change in who holds access.
Common issues
| Symptom | Likely causes | Safe check | Stop when |
|---|---|---|---|
| Newly duplicated key does not turn in the lock | Inaccurate cut on the key duplicate, worn lock cylinder, wrong blank used by the key cutter, or debris inside the keyway. | Try the original key in the same lock; if the original turns smoothly, the duplicate cut is likely faulty. Apply a small amount of graphite lubricant and retest gently. | The key binds, bends, or will not insert fully, or the original key also struggles, indicating a lock problem rather than a duplication error. |
| Transponder key duplicate cranks the engine but the car will not start | Missing or improperly programmed chip in the duplicated key, incorrect transponder type for the vehicle, or an immobilizer fault. | Check whether a dashboard security or immobilizer light stays illuminated, and confirm the duplicate was cut for the exact year, make, and model. | The security light flashes repeatedly, multiple start attempts fail, or the vehicle shows other electrical faults that suggest an immobilizer problem beyond key programming. |
| Original key is worn and copies keep failing | Years of wear have rounded the original cuts, so every key copying job reproduces the worn profile instead of the factory code. | Inspect the original under bright light for shiny, flattened teeth and compare how far it inserts into the lock compared to a new duplicate. | The worn key sticks or jams in the lock, the lock itself shows signs of internal wear, or repeated duplicate attempts fail. |
| Car key copy works in the door but not the ignition | Different cuts for door and ignition due to ignition wear, a missing transponder chip, or a laser-cut profile copied on the wrong equipment. | Test whether the duplicate turns in the ignition without forcing it and note whether the dashboard recognizes the key at all. | The duplicate will not enter the ignition, requires force to turn, or triggers the vehicle's security system. |
| High-security or restricted key cannot be duplicated locally | Patented or restricted key profiles require authorized key cutters, a security card, or proof of ownership before keys made are released. | Look for markings on the key head such as 'do not duplicate,' a patent number, or a restricted profile code that indicates authorization requirements. | A vendor offers to duplicate a restricted key without any authorization or proof of ownership, which signals an unauthorized copy. |
| Key blank does not match or feels loose in the lock | Wrong blank selected during key duplication, a cheap generic blank with soft metal, or a mismatch between house key duplication profiles. | Compare the blank's shape and thickness to the original and check for wobble when inserted partway into the lock. | The blank forces into the keyway, the key bends under light pressure, or the lock begins to jam with either key. |