Installing locks in the metal door: easier than you thought

In this article we will talk about locks. Installing locks in a metal door is an extremely important process that will require special skills and tools from the installer.

Installing a lock into a metal door most often involves inserting one of two types of locking structures: lever or cylinder. Briefly consider both types of locks.

Types of locks

Cylinder lock

installation of locks on metal doors

In other words, these castles are also called English. The lock contains a secret mechanism, where the working part is a cylinder that can only be rotated if a correct key is inserted into a cylinder well.

This mechanism (larva, core) is installed in a standard case. Thanks to the standardization, the larvae produced by different companies are interchangeable.

The keys of the cylinder locks are quite complex in shape with a lot of cuts and holes, and sometimes a side perforation. They are considered very resistant to the selection of keys.

Cylinder lock designs are two-sided and one-sided, and in accordance with the names are opened with a key either from two or from one side.

When installing this type of lock you need to make sure that it does not protrude beyond the surface of the door leaf. Otherwise, the lock should be covered with an armored lining, which is fixed from the inside of the room.

Keyless locks

install the lock in the metal door

The locking structure, where the secret part consists of a package of suvald (plates) with figured cuts, which at the time of opening the lock are pushed out by the projections on the key beard.

The plates are connected in one package and spring loaded. In the cutouts of the plates is a bolt. The movement of the bolt is possible only when when turning the key levers are brought to the desired position.

Before you install the lock in the metal door, it is useful to know that the level locks are distinguished by their strength. They are very difficult to open using brute force. The ability to resist the force depends on the number of bolts in the locking structure.

The disadvantages of this type of design include a large keyhole: it is easy to include master keys. However, modern locks have undergone a number of improvements: false grooves, recognition of master keys, etc. In case of key loss (see How to open the front door without a key), it is necessary to replace or rotate the levers in the lock.

Lock installation sequence


  • Installing locks on metal doors begins with measuring the dimensions of the lock, we transfer them to the end of the door, taking with a margin of one and a half millimeters for easy installation.
  • Grinder cut vertical holes. We pre-drill using horizontal drills, using a thin drill with a diameter of three to four millimeters. For this work we use small circles, since the large ones will not allow making cuts due to their size.
  • Using a hammer and chisel, choose a cutout. We prepare the opening made with a roller and a flat file in accordance with the dimensions of the lock. installation of a lock on a metal door
  • Next you need to draw the places where there will be screws on which the lock is fixed, we drill on the basis of: drill diameter - 0.6 millimeter. Cut the thread.
  • We install the locking structure on the screws, already knowing where the keyhole will be located, transfer them to one side of the web (usually the outer sheet).
  • Make a hole with a thin drill in the center of the planned lock well.
  • If we get exactly to the center, we attach the pad of the lock well, describe its slot for the key. Remove the lock and drill markup, controlling the imposition of the borehole lock. The work done is finally processed by a mill with a diameter of six millimeters.
  • We install the lock on the screws, check the smoothness of rotation and key output, the smoothness of the lock stroke.
  • If everything is within the limits of the norm, we do through drilling in the center of the well of the castle: through the lock to exit on the other side of the canvas. We use a long drill with a diameter of up to two and a half millimeters.
  • Perform similar work on the other hand for the manufacture of the reverse bore of the castle.
  • In the case of finishes, the same keyholes are made in it. Lining wells are mounted on the finish.
  • It remains to make holes in the end of the box for the bolts of the lock. The diameter must be larger than the bolts themselves (bolts). To do this, mark toothpaste bolts lock, close the door, turn the key, we get an imprint on the box.
  • Since the bolt holes reach fifteen or seventeen, it is impossible to do without large drills, mills or cutters. Although you can cut a general opening using a grinder, and then clean it with a needle file or a roller cutter. You need to be careful not to weaken the doorway, otherwise there will be a loose fit of the box to the door. Do not forget about compaction.
  • We install the lock and the lining (see Cover plates for decorative doors: types and installation). Good locks will last 15–20 years. Then comes the wear of the levers, keys. It is necessary to change the locks in a timely manner (see Repair of locks in metal doors).
  • Installing the lock on the metal door is over.

The basic principles of choosing a castle


  1. One imported quality lock is better than two, but bad locks.
  2. Three locks are superfluous, and two are the best option. Exceeding the required number of locks only leads to a weakening of the rigidity of the metal door structure. It is possible to install one lock using two key mechanisms, in which it is possible to block one mechanism by another.
  3. Better is one protected lock of an average level than two high levels, but unprotected.
  4. A cheap lock will not only be easier to open, it will also be problematic to operate.
  5. Installing locks in the door implies the presence of different systems: one - lever, the other - the cylinder.
  6. It is necessary to pay special attention to the protection of locking structures from opening. For example, suvaldnye prone to drilling. Cylinder - knockout, fracture, drilling. Protection against vandalism can be meaningless, and here the offender can be limited only by the inability to create a strong noise in a big house. But to counter the master keys you need to put locks with good resistance to hacking.
  7. A good level cylinder is more stable in relation to master keys and is secret, and a suvaldny design - to force action.
  8. Pay attention not only to the value of the castle, but also to the manufacturer's reputation, reviews on thematic forums, advice from consultants, etc.
  9. A good metal door should fit a good lock (see How to choose an entrance metal door).
  10. Installing locks in metal doors should not be the only measure. In addition to the actual locks, other methods of protection should be activated: alarm, concierge, video surveillance.

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