31st August 2016

Demystifying Ironmongery #3: Our Guide to Locks and Latches

Welcome to our series on demystifying ironmongery, where we investigate different aspects of hardware choice and functionality to help you make the right architectural hardware decisions. In the third issue we investigate locks and latches, outlining what every designer should know to discuss with AIs.


Locks and Latches – Two Main Types


There are two main types of locks and latches:

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  1. Mortice Lock: fitted inside the door
  2. Rim Lock: fitted on to the face of the door


Here they are in situ:


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Horizontal and Vertical Locks and Latches


There are vertical and horizontal latch locks:

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  1. Vertical latch lock: this type is the most common, and it is mainly used with lever handles but can be used with turning knobs.
  2. Horizontal latch lock: horizontal latch locks are less common, and are mainly used with turning knob handles. They cannot be used with lever handles.


Here they are in situ:

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Note the differences between mortice latches and locks:

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  1. Mortice latch locks
  2. Mortice latch
  3. Mortice dead lock


Critical Dimensions


Illustrated are the critical dimensions to look out for when specifying latches and locks.

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  1. Case depth (how far the lock will go into the door). Watch out for this dimension colliding with glass or panel inserts in your door.
  2. Backset (distance from the edge of the door to the centre of the handle rose and/or escutcheon)
  3. Case height (how high the will go into the door). Again, watch out for this dimension colliding with details in your door.


Different Types of Locking


There are 3 main types of locking, as illustrated below:

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These types correspond to different keys and keyholes:

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  1. Traditional Key
  2. Bathroom – to be used with a thumb turn and release set. The square hole is called the ‘follower.’ This can come in 5mm or 8mm square to work with different types of thumb turn and release sets.
  3. Euro profile – to be used with a Euro cylinder. These come in different options such as key-key, key-turn or as a half cylinder (half key cylinder shown)


Locks and Latches: The Main Parts


This is how the main parts fit together.


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Other Parts: Rebate Kits


Other parts for locks and latches include rebate kits. A rebate kit is for double doors with a stepped meeting edge. This brings the face of the lock forward to enable a lock or latch to be fitted to the door. They are available in 13mm, 19mm or 25mm rebate depths.


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A rebate kit in situ:


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Other Parts: Dust Boxes


Another important part for locks and latches are dust boxes, which fit behind the strike plate to give a neater finish.


A dust box in situ:


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