When it comes to replacing or buying new locks, it is important to know the different important lock measurements. Measuring a lock may seem simple, but there are different measurements required in order to choose the right sized lock for your doors. In this blog we will be looking at these measurements, what they mean, and how to measure them correctly.
Backset
The ‘backset’ is the distance from the front of the lock to the centre of the spindle. This is an important measurement to ensure that when replacing a lock, the spindle will line up to the handle hole in the door. Almost all the locks we supply come with backsets of either 44mm or 57mm, as these are standard sizes.
However, for doors that open with knobs rather than handles, the backset is recommended to be no less than 60mm, as this stops your knuckles or fingers from catching on the door frame as the knob is turned.
Lock Centres
A lock centre applies to locks only, not latches. This is the distance measured top to bottom, from the centre of the spindle to the centre of the keyhole for normal locks, or the centre of the thumbturn, if the lock is a bathroom lock.
Case Size
The case size is the total size of the case, using both height and depth. This is commonly confused with backset, but backset is only measured up to the spindle, and case size is the entire depth that goes into the door. The most common sizes for case depth are 64mm (44mm backset) and 76mm (57mm backset).
Forend Sizes
The forend is the part of the lock which sits in a cut out in your door frame, so that when fitted it is flush to the door. This is also the only part of the lock visible when a door is open. The forend is measured in height and width, the width is slightly more important as you will need to ensure that the lock is not too wide for the thickness of your door.
Please note that screw holes can also be in different positions for different manufacturers or makes of locks.
If you require any further information on lock measurements or any of our other products, feel free to give us a call or pop us an e-mail.