Locksmith glossary
Clear definitions of locks, cylinders, keys, doors, access systems, security and brands.
Technical name for the metal plate that forms the faceplate or the casing of the lock. In the trade it is used both to refer to the faceplate visible on the edge of the door and to the steel sheet of the case itself. Its thickness and quality directly influence the resistance of the assembly against drilling and levering. It is a workshop term that the end user will rarely hear, but it appears frequently in quotes and data sheets.
It allows the door to be opened from inside with a simple push on a horizontal bar, without a key or handle. It is compulsory on the evacuation exits of premises of public gathering, according to the fire protection regulations. From outside it can be locked with a cylinder. The serious mistake, still visible in many premises, is to block these doors with padlocks or chains for fear of theft: there are models with an alarm that resolve that concern without compromising evacuation.
A key whose profile is protected by a current patent, which legally prevents its manufacture by third parties while that protection lasts. It is the technical and legal basis of the restricted key. An important detail that is usually overlooked: patents expire, and when that happens the profile becomes freely reproducible. When choosing a system it is worth finding out how many years of validity remain on that protection.
A set of bolt pins distributed across several sides of the door, not just the lock side. They are also commonly found on the hinge edge, where they are called fixed or anti-crowbar bolt pins. Their aim is to prevent the leaf from being extracted by levering on the side opposite the closure. It is precisely what distinguishes a serious armoured door from a basic security-plated one, although at first glance both look the same.
A safety device formed of a transmitter and a receiver located on both sides of the passage, which stop or reverse the movement of the door if something interrupts the beam. It is compulsory on automatic doors and prevents entrapments, above all with children and vehicles. Its most common fault is misalignment or dirt on the lens: when the door starts to stop for no reason, it is usually that.
A term that in common speech designates the handle or the pull with which the door is operated, although in the trade it is also used to refer to the latch itself. This double meaning generates quite a few misunderstandings when describing a fault by telephone. If you need to explain a problem, it is best to be specific: whether the part gripped by the hand is failing or whether what does not work is the mechanism that comes in and out of the edge.
A long, thin tool, with different profiles at its end, used to manipulate the pins of a cylinder without the corresponding key. It is a usual instrument of the professional locksmith in non-destructive openings, but also a method associated with theft. Protection against it does not consist of hiding the lock, but of installing an anti-pick cylinder with irregular-profile pins, which multiplies the time needed until it makes the attempt unviable.
An English term equivalent to lock picking: manipulation of the pins one by one by means of a pick and tension wrench until achieving alignment. It appears frequently in data sheets and manufacturers' certifications, where the resistance of the cylinder against this attack is usually indicated. It is worth knowing that picking and lock picking designate the same thing, so as not to interpret as two different threats what is only one.
A case that brings together picks of different profiles along with the tension wrenches needed to work on diverse cylinders. It is a professional tool intended for non-destructive openings, whose handling requires considerable training and practice. Its existence recalls something useful for the user: the protection against these techniques does not lie in hiding the lock, but in installing a cylinder with security pins.
Each of the small cylindrical pieces that the cut of the key pushes up to the exact height needed to release the turn of the plug. They are also called pins or drivers depending on the area and the manufacturer. An ordinary domestic cylinder fits between five and six; the high-security ones, more, and with complex shapes. Their progressive wear explains why, over the years, the key needs to find the right point before turning.
Each of the cylindrical housings drilled into the body of the cylinder where the pin, the counter-pin and its spring sit. The number of chambers determines the possible combinations of the cylinder. In high-security models there may be additional chambers arranged at an angle or in several rows, not just in a single line. It is a space very sensitive to dirt: fine sand and humidity are the usual cause of a cylinder ending up seized.
It is the moving part of the cylinder, the cylindrical core into which the key is inserted and which turns when it is the correct one. As it rotates it drives the cam, which in turn operates bolts and bolt pins. Its alignment with the fixed part is what determines whether the lock opens or stays blocked. If you notice that the plug turns with play, with a metallic noise or that the key comes out with shavings, the internal wear is already advanced.
A set of periodic checks intended to detect wear before it becomes a fault: lubricating the cylinder, checking that the bolts enter cleanly and verifying that the door has not dropped. An annual check is enough for most homes, and it is worth reinforcing it in coastal areas. Most night-time emergencies start with minor symptoms that had been warning for months.
It is used as a synonym for levering in professional practice, although the term alludes more precisely to the physical principle of applying force by means of a fulcrum. It appears frequently in door and lock certifications, where resistance to this type of effort is measured. It is the attack that explains why an armoured door distributes anchors around the entire perimeter and not just on the lock side.
A fine, flexible tool that is inserted into the mechanism to locate parts, check positions or operate internal elements without dismantling the lock. It is used in diagnostics and in complex openings, especially when you have to find out why a bolt does not respond. It is a precision instrument, not one of force: its value lies in allowing the fault to be understood before deciding whether it is best to repair or replace.
A check, prior to any opening, that whoever requests it has the right to access the property. A DNI with the address, a rental contract, a deed, a bill in the applicant's name or identification by a neighbour will do. It is a guarantee for everyone, including the customer themselves: a locksmith who opens without asking anything represents a risk to their home, not a convenience.
A document that the manufacturer provides together with the security keys and that accredits who can request copies. Without it, no authorised locksmith should process a duplicate. It is the piece that makes control over the keys of a home or a business effective. It must be kept in a safe place and never together with the keys: losing it does not prevent the door from being opened, but it makes it quite complicated to obtain new copies in the future.
An expression that sums up the overall security grade of an assembly: door, frame, lock, cylinder and escutcheon working together. It is not a standardised classification, but an overall assessment. It is useful precisely because it forces the complete system to be considered. Reinforcing only the cylinder on a door with a flimsy frame raises the real level little, and that is the most frequent mistake when investing in security.
A metal piece that is fitted over the cylinder to protect it from drilling, extraction and blows. It is the most cost-effective security improvement there is after the cylinder itself, because the point through which a door is forced most frequently is precisely that one. A quality escutcheon forces the attacker to invest time and to make noise, which is exactly what whoever forces a home wants to avoid.
A credential that is read simply by bringing it close to the reader, without contact or a slot. It is the most widespread system in offices, hotels and communal garages. Its advantage lies in management: activating or deactivating a card is immediate. It is best not to confuse it with the property card of a security key, which is an accrediting document and not an opening device.
A supplement applicable to work carried out on Sundays and public holidays, with the same logic as the night one. It is worth knowing that both can accumulate in an intervention in the early hours on a public holiday. As in the previous case, the minimum requirement is transparency: the amount must be known before the professional sets out, not when the work is finished.
A policy that covers the damage the professional may cause to third parties during their work, such as damage to the door, the frame or the furniture. It is a clear indicator of seriousness and it is worth asking about it, especially in interventions on valuable doors or communal elements of a community. An established professional has no objection to accrediting it.
A fixed element, without a mechanism, that only serves to push or pull the door. It does not operate the latch, so the door must be opened with a key or left without a mechanical closure. It is the usual thing on the exterior face of home entrance doors, combined with a security lock, and also on shop and communal-entrance doors.
A metal tool with a reinforced tip, used to strike, mark or displace specific parts of the mechanism. In locksmithing it appears both in assembly and in destructive openings and in the removal of rivets and pins. It is a basic workshop tool, present in any professional kit. Its use requires precision: applied without judgement on a lock, it turns a contained intervention into damage extended to frame and leaf.