Locksmithing and Security

I had a little rant about uPVC doors a few posts back. Well I don’t much like the cylinder that often goes with it, the euro-profile cylinder.

When lever locks wanted to be operable from both sides, the clever engineers at companies like Chubb thought carefully and insightfully about key symmetry and key differs. If you have a 5-lever mortice lock key and take a look at it you’ll see that it’s symmetric and that it has not 5 positions, not 10 positions but 7 positions (bittings they are called). (Unless you have an uncommon lock like a Securefast, Walsall, or one or two others.)

The first and third levers, counting outwards, are the same. This means that a reasonably short key can be used from both sides and still have enough lever variation to allow over a thousand different key possibilities. (If we call the levers A,B,A,D, and E, then a key that is EDABADE can operate the lock from both side while only sacrificing one lever’s worth of variation.)

When some miserable creature and their miserable company somewhere wanted to use a cylinder lock (like a “Yale”), rather than a lever lock, and also to be able to use the same key from both sides, they simply doubled the thing up and had a complete cylinder at either end. Well that’s not too bad — modern manufacturing can waste materials very efficiently; and with, for example, the Swedish profile cylinder system, it can be well designed and still quite secure. However, it requires two minutes more work to fit or change a “Swedish” cylinder, so this miserable creature (does anyone know who it was?) made a one-piece, double-ended cylinder — the euro-profile — the one that’s shaped a bit like an upside down exclamation mark. And when I say “solid”, it’s only just solid. Through truly stupid design, it’s actually very fragile in one very critical place and moderately fragile in others.

And because it’s one piece there are twenty different sizes to stock; and stock twice because you need to have them in brass and in nickel finishes.

And although this awful, wasteful device is the way it is in order to allow a key to work from both sides, if you accidentally leave a key in the inside half when you go out, you can’t actually use another key from the outside if the inside one has turned a little.

And — finally getting to what prompted this moan — if one of these things is fitted in a typical 45 mm door, their having duplicated the entire damned mechanism means that you can normally only get 5 pin tumblers each side unless you use a bigger cylinder than necessary, sticking out like handlebars, but allowing you to get a more secure 6 pin tumblers each side. So there’s no way for me to give one of yesterday’s customers what is needed.

So why don’t the States and continental Europe, and increasingly the UK, carry on fitting mortice deadlocks? Well it takes a bit more work as you have to chisel a nice neat, but quite large, hole in the door, if you’re fitting the lock later on in the life of the door. Or it’s more difficult and more expensive to manufacture if you’re mass producing doors. And perhaps, a lever lock key being longer and heavier, only the pockets and handbags of the UK of the previous century were up to carrying them.

The typical, traditional, external door originally had a simple surface mounted deadbolt lock with probably only one or two levers and/or a nightlatch: a “Yale”. (And when I was a lad the door was only locked if you went away for more than a couple of days; or, at least, that’s my dim but rosy memory.)

Then most doors migrated to a latch lock — the “Yale” — and a mortice deadlock with 3, 4 or 5 levers. (Mortised means that it’s inside a hole — the mortice — in the door, rather than being surface mounted.)

Then the curse of the uPVC door and the multi-point lock (MPL) began to appear. You guess correctly that I don’t like them. They look impressive: operate the handle and all manner of impressive-looking bolts, hook-bolts, rollers, mushroom spring out and lock your door. Of course, operate the handle the other way and they all unbolt again, so a key is fitted that locks the handle preventing unbolting. But’s that’s the point. All those locks have a single point of insecurity and a single point of failure: the key and the gearbox.

So if ever your MPL starts to behave differently — making different noises or getting more difficult to operate — do get it seen to. The key should never need forcing; normally it’s the handle that does the hard work and the key gently locks the handle. If an MPL fails in the locked state with you outside or inside, it’s the devil’s own job, and a brutal one at that, to get the door open again. And if you have the worst of all worlds — a multi-point lock in a wooden door — then it’s a difficult, brutal and destructive job to get it open if it fails locked.

Actually the key often does one more job. It sets one more deadbolt, the one right in the middle of the strip. So if you’re getting a multi-point lock, make sure that there is a key-operated deadbolt because it does make the whole thing slightly more secure. And make sure that it operates easily and smoothly. If it requires force the day it’s fitted, it can only get worse. And check the guarantee and keep it, and the installer’s and the manufacturer’s details. And do, please, pass all that on to any new occupants.