How Car Key Cutting Works
Car key cutting works by a machine removing metal from a blank blade until its cuts match the depths and positions that one lock reads, either by tracing a working key or by following the key code.
Inta-Lock Car Key Guides. Updated October 2026.
The accuracy of the finished key rests on where the cuts come from, on the blank, and on the calibration, clamping and cutter of the machine. A key traced from a worn key repeats the wear, while a key cut to code carries the depths the manufacturer set for the vehicle.
Edge cut and laser cut blades are cut by different cutters and tested in the same way, at the lock. On a car with an immobiliser the cut blade turns the lock and the engine starts only once the chip in the key is programmed.
What Is Car Key Cutting?
Car key cutting is the shaping of a metal key blade so that its cuts line up the moving parts inside one lock and let that lock turn.
A car lock holds a row of small sprung plates called wafers. Each wafer sits at its own height, and the lock turns only when every wafer is moved to the one position that frees it. The cuts of the key do that work, one cut for each wafer.
Every cut has two measurements, its position along the blade and its depth. A cut in the wrong place meets the wrong wafer, and a cut at the wrong depth moves the right wafer too far or not far enough.
Cutting is the mechanical part of making a key. It deals with the blade and the lock, and it leaves the chip and the remote buttons of the key untouched.
How Is a Car Key Cut?
Five steps take a car key from a blank blade to a key that turns the lock of one vehicle.
- The blank is chosen. A blank is an uncut blade with the cross section that fits the keyway of the vehicle, and it is matched by the make, the model and the year.
- The cuts are sourced. They are traced from a working key, taken from the key code, or decoded from a lock of the vehicle where the vehicle supports it.
- The blank is clamped. The jaw of the machine holds the blade flat and square against a fixed stop, so that the first cut starts at the right distance from the shoulder or the tip.
- The cutter removes the metal. On a copying machine a guide follows the working key while the cutter follows the same path on the blank. On a code machine the cutter moves to each position and depth from the data.
- The blade is finished and tested. The burrs left by the cutter are taken off, and the key is tried in the door lock and the ignition lock of the vehicle.
Before a key is cut, identity and authority to request the work are checked. The V5C vehicle registration certificate, which names the registered keeper, and photo identification are common examples, and what applies is confirmed on the call.
How Accurate Is Car Key Cutting?
Car key cutting is accurate when the new blade carries each cut at the position and depth the lock was built for, and six factors decide whether a cut key reaches that standard.
| Accuracy factor | What it controls on the blade | How an error shows at the lock | How the factor is controlled |
|---|---|---|---|
| The source of the cuts | Whether the depths come from the data of the manufacturer or from a used key | A new blade that repeats the wear of the key it was traced from | A worn key is not used as the pattern, and the cuts come from the key code or the lock |
| The blank | The cross section and the length of the blade | A key that does not enter the keyway, or enters and sits loose | The blank is matched to the make, the model and the year of the vehicle |
| The calibration of the machine | The depth the cutter reaches at each cut | Each cut slightly deep or slightly shallow along the whole blade | The machine is set against a reference before blades are cut on it |
| The alignment in the clamp | The position of each cut along the blade | Cuts of the right depth in the wrong place, and a key that turns only when drawn out a little | The blade is seated flat against the stop of the jaw before the first cut |
| The condition of the cutter | The angle and the floor of each cut | Ragged cuts and a key that drags on the way in and out | A worn cutter is changed before it marks the blade |
| The finishing | The edges left on the blade after the cutter has passed | Burrs that catch inside the keyway | The blade is deburred and the key is tried in the locks of the vehicle |
The table sets out what decides the accuracy of a cut key and gives no tolerance figure. The work itself belongs to car key cutting in Leicester, where the key is cut at the vehicle and the source of the cuts for an individual vehicle is confirmed on the call.
A car key is cut at your vehicle in Leicester or Leicestershire, and a quote is agreed before work begins.
Call Matt on 0116 442 2084Is a Copied Key as Accurate as a Key Cut to Code?
No, a copied key is only as accurate as the key it is traced from, while a key cut to code carries the cut depths the manufacturer set for that vehicle.
A copy traced from an unworn key on a calibrated machine turns the lock in the same way as its pattern. A copy traced from a worn key carries the wear forward, and a copy of a copy passes the small error of each generation on to the next blade.
A key cut to code starts from data and not from metal, so the wear stays on the old blade. The key code is a record of the cuts, and it lets a machine make the blade with no key present.
What Are the Signs of a Badly Cut Car Key?
Four signs point to a badly cut car key, and each one shows at the lock and not at the remote buttons.
- The key turns only with a wiggle. A key that turns only when it is rocked or jiggled has cuts close to the right depth and not at it, so the wafers line up for a moment and then fall out of line.
- The key turns only when drawn out a little. A key that turns only when it is pulled back from the lock has its cuts in the wrong place along the blade, which points to the alignment in the clamp.
- The key is stiff on the way in or out. A key that drags in the keyway carries burrs or ragged cuts, or it is cut on a blank with the wrong cross section.
- The key turns one lock and not the other. A key that opens the door and does not turn the ignition lock, or the reverse, sits at the edge of what the two locks accept.
A worn lock produces the same four signs with a correctly cut key, so the signs alone do not prove that the blade is at fault.
How Is a Laser Cut Key Cut Differently?
A laser cut key is cut by a small rotating cutter that mills a track into the flat face of the blade, while an edge cut key has notches cut into its edge.
The name is misleading, because no laser touches the metal. The cutter of a laser cut key travels along the blade and from side to side, and the depth of the track stays the same along its length. The shape of the track is what the lock reads.
An edge cut blade is thinner and carries its cuts on one edge or on both. A laser cut blade is thicker, and its track runs down the centre of the face or along the outer edge of the face. The test is the same for both blade types, the cut key turning the locks of the vehicle.
Does a Cut Key Start the Car?
No, a cut key alone does not start a car with an immobiliser, because the blade turns the lock and the chip in the key is what the immobiliser reads.
On a car with an immobiliser, a correctly cut key with no programmed chip opens the door and turns the ignition lock, and the engine does not start. Cutting is the mechanical half of a new key and programming is the electronic half.
A car with no immobiliser starts on a correctly cut blade alone.
Which Jobs Go Together With Key Cutting?
Four questions sit beside the cutting of the blade, and each one leads to a different job or a different guide.
How Does Cutting a Spare Key Differ From Cutting With No Key?
Cutting a spare key starts from a key that still works, while cutting with no key starts from the key code or from a lock of the vehicle.
With a working key in the hand, the blade is traced or cut to code. That job belongs to the spare car keys service, which makes the second key while the first still works. With no key at all, there is no pattern to trace, and the cuts come from data or from the lock.
How Does Key Cutting Differ From Key Programming?
Key cutting shapes the metal blade, while key programming pairs the chip in the key with the immobiliser of the car.
The two jobs use different equipment and fail in different ways. A cutting fault shows at the lock, and a programming fault shows as an engine that turns over and does not start. The electronic half is set out under what car key programming is.
How Does the Key Type Decide the Blade?
A plain key, a remote key, a flip key and a keyless fob each carry a blade of some kind, and on a keyless fob the blade is the emergency key held inside the case. The differences between them are set out in the car key types explained one by one.
Why Does a Correct Key Stick in a Worn Lock?
The opposite situation is a blade cut correctly to code that still sticks in one lock. The fault then sits in the lock and not in the key, because the wafers and the keyway wear with years of use.
A new blade does not cure a worn lock. That work belongs to car door lock repair, the service for the lock and not for the key.
For a car key that sticks, or a single key with no spare, the phone is answered 24 hours a day, and what the visit covers is confirmed on the call.
Frequently Asked Questions
What is a key code?
A key code is a string of characters that records the cuts of a key, so that a machine makes the blade with no key present.
The code belongs to the locks of one vehicle. A blade cut from it carries the depths set by the manufacturer and none of the wear of a used key.
Why does a newly cut car key not turn smoothly?
A newly cut car key does not turn smoothly when its cuts sit at the wrong depth or position, when burrs remain on the blade, or when the lock itself is worn.
The first two causes sit in the key and are put right by cutting the blade again. The third sits in the lock.
Does a copy of a copy still work?
A copy of a copy works only while the error added by each generation stays inside what the lock accepts.
Each tracing passes on the wear and the small error of the blade before it. A key cut to code breaks that chain, because it starts from data.
Does copying a key harm the key that is copied?
No, copying a key leaves the working key unchanged, because only the guide rests against it and the cutter meets the blank alone.
The working key goes back on the ring as it was.
How much does car key cutting cost?
The cost of car key cutting is quoted for the individual key, and a quote is agreed before work begins.
Three factors move the figure, the blade type, whether a working key is present to supply the cuts, and whether the key is programmed as well as cut on a car with an immobiliser. No price list is published.
How long does it take to cut a car key?
The time to cut a car key depends on the blade type and on whether the cuts come from a working key, the key code or the lock.
The time for an individual key is confirmed on the call from the make, the model and the year.