Locksmithing and Security

Your insurance policy might ask for for patio doors, etc. to be fitted with mortised rack bolts. Unlike the most obvious kind of bolts which would be fitted to the face of the door, mortised bolts are fitted within the door itself. From the outside all you see is a little hole into which you put your “star” key and which you then turn to extend or withdraw the bolt.

Rack bolts are very strong but there are a couple of points you should bear in mind.

Keep an eye on your builder and check that they don’t drill the key hole right the way through, as on one door I saw the other day! The whole idea is negated somewhat if there’s a keyhole on the outside!

Although they are strong when deployed, their winding mechanisms (the “rack”) are not strong. If you can’t operate the bolt with light finger pressure, stop. If you force it, you will strip the teeth off the rack. If that happens in the locked position then you will face an expensive exercise getting it open again. If the door is warped or swollen, try relieving the pressure on the bolt by gently pulling on the door handle while trying to wind the bolt in or out. If it’s getting more and more difficult to operate, get it seen to before it breaks.

No more than a couple of turns of the key are needed. Any more and, again, you will tend to strip the teeth. Try it with the door open while feeling or watching the bolt; note how many turns are needed.

If your rack bolts are fitted to windows, they might be the short variety. These aren’t much good as the bolt is so short. If you have to fit these (usually because the frame is too small for the regular size), make sure they aren’t recessed any more than they need to be. Recessing is when you chisel a shallow depression in the door edge for the bolt’s faceplate, and in the frame for the keep. I recently visited a property where there was already a 3 mm gap between the window and the frame, and where the fitter had gone on to recess the bolt and the keep each by 2 mm more than needed. Result? The bolt wasn’t actually engaging at all!

The “French” doors you usually find in the UK are not French at all, as you’d probably expect. As you close proper French double doors they fit together by one door having a rounded edge profile and the other door having a cupped edge profile. When they’re properly sized and when the wood is properly seasoned, prepared and painted so that it doesn’t expand or shrink too much, this is an excellently draught-proof arrangement. Naturally it’s getting harder and harder to get proper doors that are properly fitted.

Here in the UK, “French” double door fit together with rebates. The edges where the doors meet have L-shaped profiles. This is nearly impossible to draught-proof.

Fitting locks (deadlocks or sashlocks) to either countries’ arrangments is challenging. Normally a rebated door will have a rebated lock. The lock will either be specially shaped or will have an adapter such that the bolts and keeps (boltholes) can still be placed centrally, across the rebate.

A lazy or ignorant fitter might be tempted to fit the lock off centre so that they don’t have to deal with the step shape of the rebate. Unfortunately this means that the bolt keeps will find themselves in the thin and fragile sticking out part of the other door. And the lock case will be too close to the face of its door and easily broken out and opened.

Even when fitted properly rebated doors won’t be secured particularly well by a deadlock or sash lock. Most deadlocks and sash locks, for example, lose their BS (British Standard) rating when used between rebated double doors.

You really need to fit mortised bolts as well. Mortised means that the bolts are inside the door rather than screwed to its face. They are also known as rack bolt or star-key bolts because a star shaped key that goes into a small hole is used to wind the bolt in or out.