Three-point locking

Three-point locking is a locking system installed in cabinet or locker doors to enable more secure locking. Whereas in single-point locking, the door on a cabinet locks only at the point where the key is turned, halfway up the edge of the door, three-point locking enables the top and bottom of the door to be simultaneously secured. This is accomplished by attaching two long steel rods to the lock on the inside of the door, which extend vertically upwards and downwards: when the lock is turned, the rotary movement of the latch on the inside of the door translates to vertical movement in these rods, with the result that the upper rod moves upwards by an inch or so, and the lower rod moves downwards similarly. This causes the ends of the rods to move through small holes in the flanges at the top and bottom of the door, resulting from the metal of the door being turned inwards, and the rods then move a short distance into holes in the metal surrounding the door. This effectively immobilizes the top and bottom of the door, and greatly increases the security of the door-locking compared to a door with only single-point locking.

Near the holes in the top and bottom of the door, some restraining device is provided for the rods to pass through, to prevent them from falling away entirely when in the unlocked position, and thus not inserted into the holes in the door. This consists of either a rubber or plastic gasket fitted into the holes in the door and protruding up or down a short distance, or else a small metal plate with a hole in it welded to the inside of the door through which the rod extends in any position.

Single-point locking may provide adequate security for some situations on tiered lockers, as the doors are shorter, and therefore more difficult to force open; however, the taller doors of full length lockers and cabinets are more susceptible to the application of leverage. This is the reason three-point locking is usually found on single-tier lockers, and is certainly highly recommended in cases where it is optional.

This system is occasionally wrongly referred to as three-pin locking. This name is incorrect because only two pins or rods are involved, the third locking point being the latch itself inside the door.

In Australia, a locker or cabinet under certain weight limits cannot be legally used to store firearms unless it uses three-point locking and is bolted to either the floor or a wall.

Locksmithing & Lock picking

Topics	Electric strike Key control Key relevance Lock bumping Lock picking Lockout-tagout Maison key system Rekeying Single-point locking Three-point locking

Components	Bitting Bolt stump Break Interchangeable core Key blank Key code Keyhole Lockset Shear line Split pin

Key types	Berlin key Bump key Change key Master key Skeleton key Smart key Tubular key Transponder key

Lock designs	Bored cylindrical lock Bramah lock Cylinder lock Disc tumbler lock Electromagnetic lock Electronic lock Key retainer Lever tumbler lock (Chubb detector lock) Magnetic-coded lock Magnetic keyed lock Mortise lock Padlock Combination lock Rotary combination lock Time-delay combination locks Pin tumbler lock (Snib) Protector lock Relocking device Time lock Tubular pin tumbler lock Warded lock Wafer tumbler lock 5 lever lock

Specific lock types	Bicycle lock Chamber lock Child safety lock Dead bolt Keycard lock Kensington Security Slot Luggage lock Power door locks The Club TSA lock

Tools	Lockpick Slim Jim Snap gun Tubular lock pick

Related	Bolt cutter Door chain Exit control lock Famous locksmiths Interlock (engineering) Keychain Key (engineering) Lock manufacturers Lock puzzle Lock snapping Locksport Two-man rule

Category:Locksmithing Keys Locks Book

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