- Duplication inherits wear. Originating to code produces a key that works every cylinder on the car.
- VIN to key code lookups require verified credentials and proof the customer owns the vehicle.
- The door cylinder is usually less worn than the ignition and easier to decode.
- A cylinder that will not decode cleanly is telling you it has a mechanical fault.
Duplication and why it drifts
A duplicator traces the existing key with a stylus while a cutter mirrors the movement onto a blank. Every duplication inherits the wear of the key it copied, then adds its own small error from stylus play and blank tolerance. Copy a copy of a copy and you eventually get a key that will not turn.
That drift is why a customer who says my spare has never worked properly usually has a third or fourth generation duplicate. The fix is not another duplication. Originate a fresh key to the factory code and the problem disappears, and both keys will then work in every cylinder on the car rather than only the ignition.
Duplication still earns its place. It is instant, it needs no vehicle information, and for a house key or a mailbox key it is entirely adequate. For automotive work treat it as a convenience rather than a standard.
Origination by code
Every vehicle lock is cut to a code. That code maps to a specific depth at each cut position, and a code cutting machine drives the cutter to those exact depths. The result is a key cut to factory specification rather than to a worn copy.
Codes come from three places. Some are stamped on the original key or on a metal tag delivered with the car. Some are retrievable from the manufacturer through a licensed locksmith key code service, which is one of the strongest business arguments for holding proper credentials. Some are derived from the vehicle identification number through a subscription database, which is the route most mobile locksmiths use daily.
Code services check who is asking. Expect to prove your identity, your business license where the state requires one, and the customer's ownership of the vehicle. Treat that check as the price of admission rather than an obstacle. It is the same check that keeps the trade legitimate.
Decoding the lock
When there is no code and no working key you read the lock. On wafer cylinders a set of thin decoding picks can feel each wafer height in turn and give you a working combination. On high security laser track cylinders a lishi style tool decodes and picks in the same operation, showing the cut depths on a printed scale as it lifts each wafer.
On a car with a hidden door cylinder that is often the easiest lock to read, because it has seen less wear than the ignition and fewer wafers. Read the door, cut the key, then confirm it turns the ignition before you commit to programming.
Decoding is also a diagnostic. A cylinder that will not decode cleanly usually has a broken wafer, a bent retainer or years of debris packed in behind the face. Finding that out with a tool is far cheaper than finding out with a freshly cut key that will not turn.
Common Questions
Why does a laser cut key cost more than an old style key?
The blank costs more and the machine that mills the track costs several thousand dollars. A shop that only owns an edge cutter has to send the work out or turn it down.
Can a worn key be copied accurately?
Copying a worn key copies the wear, and the second copy is worse. Cutting to the original factory code produces a key to spec instead. That needs proof of ownership and the code from the maker.
My new key turns but feels rough. Is that normal?
No. A rough turn usually means a cut is one depth out or the blank has burrs left on it. Ask for it to be deburred and rechecked before you leave, because a rough key wears the lock.
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