Locksmithing and Security

One of the commonest calls is, “My latch key turns a little bit but then stops.”

If it’s a Yale latch lock and it’s on the right-hand side of the door, then a loose snib might just have fallen down when the door was slammed shut. (The snib is the tiny button or lever that holds the bolt open or closed. A dropping snib on an ERA on the other-hand, is only going to lock you out if it’s on the left-hand side of the door. (These handings are as if you’re standing outside.)

Another possiblity for any lock with a snib is that there’s a huge gap between the door and the frame; and you left the lock snibbed yet managed to slam it shut.

One, more disturbing possibility you should bear in mind however, is that if a thief has broken in through a window or throught the back door, (s)he will usually snib the front door’s latch so as to get some warning if you return.

So, enter the premises cautiously. Send the dog in first.

If you’re choosing a latch lock, some can be snibbed open or closed, but some can only be snibbed open (also known as a hold-back).

What do you do if there are windows at the back of your property — which must apply to just about everybody except non-ground-floor flat dwellers?

You can consider grilles. I don’t like the huge concertina grilles very much. They look overpowering even when drawn back; and they can trap fingers. Strap grilles are quite good; they’re fairly unobtrusive.

For a general increase in security at the rear once you fitted good locks, the next thing to sort out is light. Obviously there are daytime break-ins so it’s not an absolute. But it’s a good deterrent when a thief raising its ugly head over the fence/wall/trellis suddenly activates a nice powerful light.

But do have them infra-red activated, do adjust them for sensitivity and for daylight level, do put them up high and do get them with a metal grille over the front.

Customers quite often ask me what the best lock would be. However, quite often we are standing next to a door that the big, bad wolf wouldn’t even have to huff over — one small puff and it would be open.

The physical strength of the the door and frame are just as important as the lock. This is especially true around here (London) where nearly all break-ins I attend are literally that: smashing the door in.

A solid door is better than a hollow door or a panelled door. Raised moldings can make it look nicer; panels simply make it easier to burst through. If you must have panels — of wood or of glass — you really need to consider a mesh or a grille on the inside. If grilles or meshes over panels are aesthetically unacceptable then you need to consider a monitored alarm or a big dog.

I’m sometimes asked to fit another mortice deadlock, but in a door that’s too thin or too insubstantial. I’m afraid that cutting a big hole in a door that’s less than 44 mm thick, or that’s hollow, simply makes it easier to burst open.

Are the door or frame cracked or split, especially around the locks and their keeps? Minor cracks and splits can be dealt with via strengthening plates and bars. Major cracks or splits really require the attention of a good carpenter.

Many customers don’t realize that their rimlatch (their “Yale”) lock might be of the double-locking type.

If there’s a keyway in the inside handle, what’s it for? Well, first of all it might not work. If you had the outside cylinder (or barrel) changed at some point because of lost or otherwise compromized keys, chances are that you didn’t get the inside cylinder re-keyed at the same time, so it needs a different, probably lost, key.

Its purpose is twofold: to lock the bolt and to lock the inside handle/knob. I’ll come back to a more detailed explanation of the former in a moment.

Why would you lock the inside handle? Because if someone has broken into your property at the back, they would probably prefer to carry your plasma screen TV out of the front door. But if you’ve locked the handle they can’t.

Your rimlatch might still be double locking even if there’s no keyway in the inside handle. It’s quite often the case that you can lock the bolt and the inside handle/knob if you turn your key full circle in the opposite direction to the normal, unlocking direction.

Now, the main reason for this post if you’ve the latter variety of double-locking rimlatch, is to warn you that you might lock someone in one day. It goes like this: you never realized that the latch was double locking; you left as usual pulling the door shut behind you; you realized you’d forgotten your umbrella; you unlatch the door leaving your key in the lock as you grab your umbrella; then you pull the door shut again and turn the key. Now anyone left inside can’t get out. Even if they have their outside key they can’t unlock the inside handle. The only thing they can do is call to a hopefully honest passerby and pass them their key through the letter slot.

By the way, if your key takes three-quarters of a turn to open the door, rather than the more normal quarter turn, then it’s possibly a double-locking lock that’s had its double-locking disabled.

(In the UK, you may well have a mortice lever deadlock as well as a latch. Once that’s locked then your door has also been secured in both directions. For some reason mortice deadlocks never gained popularity in the States or in continental Europe, where break-ins are easier — although not necessarily more common — Brits seemingly being a villainous lot.)

What do we mean by locking the bolt? A latchbolt latches: you don’t need to use any key in order to make the door shut behind you. This happens because the latch is sprung and the closing face of the latchbolt is angled whereas the opening face of the latchbolt is flat. This convenience is also a security hazard because a burglar might be able to get something to push against the sloping face and unlatch the lock. So that’s why we might want to lock the latchbolt.

(If a lock bolt is unsprung and a key required both to shut it and to open it, it’s what we call a deadbolt — it’s not live, i.e. sprung.)

Some expensive locks — like an Ingersoll — automatically deadlock as they latch shut.