Definition of a mortice lock

A little about mortice locks  found in most UK homes

It’s the morning after the night before. Yes, I’m writing this the day after Eurovision. There were songs, some were good, some were bad, the UK didn’t win, and the slightly wet chap singing the song from Portugal won. I think that clears it all up. I’ll be honest, my Eurovision analysis is not what it could be. Fortunately that’s not really my area of expertise and if you’re wanting in depth socio-political commentary about the scoring system (so reassuring when Greece and Cyprus give each other 12 points), I’m afraid you’ve come to the wrong place.

Happily, I do know a bit more about locks than Eurovision and, given that the former is my bread and butter, it’s a good job I do. So today I won’t be talking about Bucks Fizz, Brotherhood of Man or Dana International, but rather about locks. I thought you may be interested in the types of locks I encounter in my day to day working life. If you’re not, well you’ve already read this far so you may as well keep going – the fallacy of sunk costs, and all that.

This month I’ll talk a little about mortice locks which can be found in one form or another in most homes in the UK. They have admittedly been a little usurped recently with the advent of uPVC doors replete with their own cylinder locks, but there does also seem a bit of a swing back to mortice locks in some new builds, given the level of security they provide.

How a mortice lock works

A mortice lock is so called because of a mortice (also known as a pocket, or simply a chiselled away section) that is cut inside the edge of the door in order to accommodate the lock case. Historically this lock case has housed a lever lock, but again, following the upsurge in cylinder locks, we now find mortice locks are often combined with cylinder rather than the lever mechanisms. This means that now when we talk about mortice locks, we’re generally talking about one of two systems – the lever mortice or the cylinder mortice.

The classic lever mortice lock comprises a series of levers within the lock mechanism, housed inside the mortice. These levers can be raised up and down to different heights, depending on the dimensions of the key that is inserted into the lock. If the correct key is put in a locked door, then the levers all raise to their specific heights, the key can turn and the bolt will be unlocked, allowing entry through the door. If the key is of an incorrect design then the levers will be raised to non-matching heights and if these are only a fraction of a centimetre out, this will prevent the key from turning and deny access.  Generally speaking, the more levers that the lock has in place, the more secure the design. For day to day use, we would use 2, 3 or 5 lever locks, the latter of which is the most secure for domestic use. There are also 7 lever locks available, but these are usually restricted to use in safes and gun cabinets.

As mentioned above, we now also have cylinder mortice locks. In these, rather than the lever system, a key is inserted in a cylinder which, when it is turned, locks or unlocks the door. You may well have heard of the Euro-cylinder locks which are now widely used, especially on uPVC doors. These locks had the early weakness of being easily breached in a matter of seconds by burglars through the technique of “snapping”, but they have since evolved and many antisnap versions are now on the market.

When buying a cylinder lock, ALWAYS ensure it’s an antisnap variety – it really does make all the difference, ideally the Ultion 3 star.

A mortice lock of either variety is fitted by cutting into the side of a door to create a space in which the lock casing can be fitted. It could be argued that this procedure in itself weakens a door’s structure, in particular a timber model, but it is also accepted that the extra protection provided by a mortice lock more than outweighs this drawback. As the mortice lock is built into the door rather than simply affixed on, it can house a much more durable mechanism, affording better protection than a flimsier example.

Choosing the right mortice lock

If you look into purchasing mortice locks you’ll find that there a wide variety available on the market. As well as the two models I’ve mentioned above, you will come across Mortice Deadbolts, Mortice Eurolocks, Mortice deadlocks, Mortice Sashlocks and probably dozens more. Don’t let all these confuse you though. The crucial aspect is that a mortice lock is defined by the mortice (or pocket) that it sits in within the door. There are a whole range of lock mechanisms that can then be fitted into this mortice, and they will then be described as a mortice style lock.

If I can throw in a personal and professional recommendation, I find mortice locks are still a real winner, ensure a high level of security and I would always recommend they be used. A British Standard mortice lock with a 20mm throw bolt provides an excellent level of security and is one I frequently fit myself.