A situation where a single set of keys is lost or broken inside a mechanism often puts the property owner in front of a difficult choice: a complete replacement of the lock or an attempt to recreate a duplicate. Making keys on the larva of the lock It is a highly accurate technical procedure that allows you to restore access without dismantling the entire doorway or replacing an expensive shut-off system. Modern technology allows the masters to literally “see” the internal geometry of the locking device, even if the key was not in their hands.
This process requires not only specialized equipment, but also deep knowledge in the field of technology. lock-mechanics and materials science. Unlike simple code cutting, working with a disassembled larva (cylinder) involves re-creating the milling cutter profile, the depth of the cuts and the location of the pins with micron accuracy. An error of even a few hundredths of a millimeter can cause the key to turn around but not open the door, or, worse, jam the mechanism when turning.
Owners often underestimate the complexity of modern cylinder design. Inside. larvae There can be not only standard pins, but also magnets, balls, as well as complex systems of protection against drilling. That is why the procedure for restoring the key on the disassembled mechanism is considered one of the most difficult in the locksmith business and requires contacting qualified specialists with the appropriate equipment.
⚠️ Warning: Attempts to disassemble a complex mechanism without experience often lead to irreversible damage to pins and springs, which makes it impossible to manufacture a working key and requires a complete replacement of the cylinder.
Key Profile Recovery Technologies
The basis of the process is the precise determination of the geometry of the working part of the key. There are several methods that are used depending on the type of lock and the safety of the elements inside the larva. The most modern and accurate method is the use of 3D scanning. The specialist scans the inside of the cylinder or key remnants if they get stuck, creating a digital model. This model is then downloaded into the CNC machine software.
Another method is mechanical reading of pin depth codes. The master uses special probes and measuring tools to determine the height of each pin in the keyhole. The data obtained are recorded in the code correspondence table. Code cards allow you to translate the physical dimensions into the digital values required for the machine. This method requires high qualification and sensitivity of the hands of the master.
The third option is to create a cast of the inner cavity, if the design of the lock allows it. However, for modern suvald and cylinder mechanisms, this method is rarely used due to low accuracy and the risk of leaving foreign materials inside the mechanism. In most cases, a combination of visual examination under a microscope and mechanical measurements is used.
- 🔍 3D scanning of the internal geometry of the cylinder to create a digital model.
- 📏 Mechanical measurement of pin depth using calibrated probes.
- 🖥️ Programmatic calculation of the profile based on the code tables of the manufacturer.
- 🧪 Chemical or physical analysis of metal for the selection of workpieces.
Equipment required for accurate operation
The quality of the duplicate product directly depends on the equipment park used. To work with larvae without the original key, ordinary household copiers will not work. Professional is required milling-machine (Numerical program management). Such devices are capable of cutting out a complex key profile with micron accuracy, which is critical for high-secret mechanisms.
In addition to the machine, in the arsenal of the master should be specialized tools for dismantling. These are sets of screwdrivers with magnetic tips, tweezers with anti-reflective coating, and extractor to retrieve the wreckage. For the analysis of the internal structure, digital microscopes are often used with the ability to display the image on the computer screen, which allows you to consider in detail the notches and scuffs on the pins.
An important element is the code database. Major manufacturers of castles, such as Mottura, Cisa, Mul-T-LockThey have their own coding systems. Access to current databases allows the wizard to quickly match the measured parameters with factory standards. Without this step, key recovery turns into a long process of selection by pumping, which is unacceptable for expensive security systems.
Always require a master to demonstrate the workpiece before starting milling. Make sure that the profile of the workpiece (height, shape of the head) fully matches the original type of your lock.
Stages of manufacturing duplicate
The process of restoring the key on the larva takes longer than a regular slicing. The first stage is always the diagnosis. The master must determine the type of mechanism, its model and the state of the internal components. If the larva is removed from the door, it is carefully cleaned of lubrication and dirt, so that nothing interferes with accurate measurements. Then there is the stage of direct removal of dimensions.
After obtaining all the necessary data, the master selects the appropriate blank. The metal of the workpiece should be of a certain hardness: too soft key wears out quickly, and too hard can damage pins during operation. On the CNC machine, a milling program is set, and the process of creating a working profile begins. In the process of work, manual decorating of sites may be required.
The final stage is testing. The manufactured key is inserted into the larva. It should be in smoothly, without undue pressure. No snorting or snoring should be heard when turning. Work course It should be complete. If the key does not work the first time, the process is repeated with the adjustment of the parameters. Only after a successful test is the key given to the client.
☑️ Checking the quality of the work of the master
Difficulties with high-secret locks
Modern security systems, such as Abloy Protec2 or Mul-T-Lock Interactive+This creates a significant obstacle for key manufacturers. These mechanisms use movable elements inside the key itself, as well as pins of complex shape (for example, in the form of a crescent or with side cutouts). To make such a key, having only a larva, is extremely difficult and often impossible without access to the factory key card.
The main problem is the presence of protective elements. Inside the larvae can be false pins that block the key turning at the wrong depth or angle of inclination. It is also common to use hardened inserts that do not lend themselves to standard drilling or measurement methods. In such cases, the wizard may need access to the manufacturer’s closed databases, which are not available to everyone.
Another problem is the presence of magnetic elements. If magnets are used in the key, their location and polarity must be strictly observed. An error in polarity will cause the magnets to repel the pins rather than attract them, and the lock will remain closed. To work with such systems requires specialized equipment to check the magnetic field.
⚠️ Note: For locks marked “Do Not Duplicate” or a proprietary profile, the key can only be made if the owner presents the card or documents for the property.
Comparison of methods: CNC vs. hand-cutting
When restoring keys on the larva, the choice of the cutting method plays a decisive role. Manual cutting on copier machines is only suitable for simple suvald keys or low-secret cylinders. For complex profiles where the geometry of bevels and micro-protrusions is important, handmade work cannot provide the required accuracy. CNC machines operate on a digital model, excluding the human factor and hand tremors.
The cost of work on CNC equipment is higher, but this is justified by the key resource. The cutter used by the machine creates perfectly smooth walls of the saw, whereas the manual method can leave micron burrs. These burrs in the process of operation turn into metal shavings, which clogs the larva and leads to its breakage after six months or a year of active operation.
The table below compares the characteristics of the two methods for larval recovery:
| Parameter | Hand-cutting | CNC slicing | Laser cutting |
|---|---|---|---|
| precision | Low (±0.1 mm) | High (±0.01 mm) | Maximum |
| Key types | Simple, suvald | Cylinders, perforated | Flat, laser-based. |
| Speed. | Quickly (5-10 minutes) | Average (20-40 min) | Long time (up to 1 hour) |
| Key resource | Medium. | High-pitched | Very tall. |
For locks more than 5000 rubles, the use of CNC milling is a prerequisite for preserving the guarantee and resource of the mechanism.
Cost and time of work
The price for the manufacture of the key on the larva is formed from several components: the complexity of the mechanism, the urgency and cost of the workpiece itself. A simple cylinder key is cheaper than recovering a perforated key with magnets. Also affected is the need for preliminary dismantling or defective mechanism, if it was damaged in an attempt to break.
The deadlines vary from 30 minutes to several days. If the master has the necessary workpiece and program for the machine, the work takes about an hour. In the case of rare lock models, the workpiece may need to be ordered from the supplier, which increases the waiting time to 2-3 days. The urgent departure of the master with a mobile laboratory to the scene is usually more expensive than a visit to a stationary workshop.
It is important to understand that saving on quality of manufacture can lead to double costs. A cheap but inaccurate key will quickly disable an expensive larva, the replacement of which, together with the installation work, will cost many times more than the initial high-quality manufacturing of the duplicate. Therefore, the price in this case is an indicator of the technologies used.
Why do some workshops refuse to make keys on the larva?
Many workshops work on the principle of "key to key", using ready-made samples. Working with a disassembled larva requires the availability of expensive CNC equipment, code databases and a highly skilled master, which is not everywhere.
Frequently Asked Questions (FAQ)
Can you make a key if the larva is in the door and it can not be removed?
Yes, it's possible, but it's harder. The master uses the method of casting or impression (if the type of lock allows). However, the accuracy will be lower than when working with the removed larva, and the risk of damage to the mechanism when trying to extract the debris is higher.
How long does it take to produce a complex perforated key?
The average process takes from 40 minutes to 1.5 hours. This time is needed for accurate measurements, CNC machine programming, milling and, most importantly, key testing and fitting.
Will the key made from the larva last as long as the original?
If a high-quality workpiece from brass or milling was used and milling was carried out on a CNC machine, the resource of such a key is not inferior to the factory one. The main thing is the absence of micron defects in the profile.
What if the key made by the larva does not turn?
Don't use force. Go back to the master for the finishing. It may be necessary to polish certain areas or correct the depth of the saw. Independent sawing of the key with a file is strictly prohibited.
Do I need to change the lock after making the key on the larva?
No, you don’t need to change the lock unless it was damaged in the process of losing the key or failed opening attempts. The procedure for manufacturing a new key does not require replacing the locking device.