Change or rekey · London
Deadbolt Installation
The old deadbolt has grown lazy.
In plain words
If your door already has a knob or lever bore and nothing above it, adding a deadbolt is a boring job in the literal sense. A jig clamps to the door at the right height, usually 140 to 150 mm above the knob centre, and guides a hole saw through the face and a smaller bit through the edge. The locksmith mortises the edge so the bolt faceplate sits flush, sets the bolt to the door's backset, then fits the cylinder outside and the thumb-turn inside. The frame is marked from the bolt itself, bored and chiselled for the strike, and the lock is tested open and closed.
How the visit goesThe door from the garage into the kitchen closes on a passage knob with no lock at all. Anyone who opens the garage is one turn of a handle from the house, and the insurance renewal form has a question about exactly that.
Deadbolt Installation
How the visit goes
Glass, sidelights and what is within reach
Glass changes the conversation about which deadbolt to fit. A pane in the door or a sidelight within an arm's reach of the lock means an inside thumb-turn could be reached by breaking the glass, which is why double-cylinder deadbolts are sometimes suggested. The locksmith measures the distance from the glass to the lock, notes whether it is tempered, laminated or plain, and lays out the options: a captive thumb-turn that needs a key only when you choose, a laminated pane or a tested security film that can delay an arm, or moving the bolt height. The aim is a door that keeps a stranger out and still lets everyone inside leave with one turn of the hand.
Cutting a pocket the bolt can fill
The strike is located from the bolt itself rather than from a measurement. The bolt tip is chalked, the door is closed and the bolt is thrown firmly against the jamb to leave a mark at the true centre. The locksmith bores the pocket there with a 25 mm bit to a depth of at least 28 mm, so a 25 mm bolt seats fully and reaches its deadlocked position instead of stopping short and feeling stiff. The pocket is checked with the bolt extended before any plate goes on, because a strike screwed over a shallow hole hides the fault until the first cold morning when the door has moved.
A safer way out as well as a stronger way in
With a thumb-turn inside, everyone in the household can leave through this door without hunting for a key, day or night. The locksmith walks the family through the thumb-turn and shows children how it turns. If a double-cylinder bolt was replaced, the inside key is no longer needed at all and can be retired. Where glass sits near the lock, whatever measure you agreed on, a thumb-turn that locks with its own small key, a laminated pane, or a tested security-film system that can delay an arm's reach, is in place, so security did not come at the cost of a clear way out.
Deadbolt Installation
In the van
Boring jig and 54 mm hole saw
Jamb reinforcer
Strike box
75 mm (3 in) strike screws
25 mm auger bit
Deadbolt Installation
What affects the quote
Door material
Solid wood, steel-clad and fibreglass doors are each cut differently. Metal skins call for slower cutting and cleanup of filings, so the material is one of the first things a quote takes into account.
Removing and disposing of the old hardware
Some visits end with the old deadbolt and strike left with the homeowner, and others ask for it to be removed and hauled away. Taking the old hardware away adds a small amount of time and is agreed before the new deadbolt goes in.
Mechanical, keypad or smart lock
Electronic deadbolts carry a different hardware line and add setup time for codes, pairing to a phone and a walk-through, all of which appear as their own entries.
What to have ready
- Would you like a keyed deadbolt, a keypad, or a smart lock you can control from a phone?
- Do you own the home, rent it, or manage it for someone else?
- Do you want the new deadbolt to work on the same key as your other doors?
Deadbolt Installation: questions
QuestionsI just moved in. Should the new deadbolt be keyed to a new key?
It is a good moment for it. Nobody knows how many copies of a previous owner's key exist, so pinning the new bolt, and the rest of the exterior doors, to one fresh key retires all of them at once. Lock manufacturers list a move as one of the main reasons to rekey. You come away with a known number of keys, each tested in every door it is meant to open.
How do I look after a deadbolt once it is installed?
Very little is needed. Each spring and autumn, lock the door from inside and feel whether the bolt still goes home without the door being pulled; if it hesitates, the door has moved with the season and a small strike adjustment restores it. Whatever lubricant the lock's own maker specifies keeps it smooth, often a dry PTFE or graphite type in the keyway and along the bolt, though some cylinders are meant to be serviced with oil. In winter, wipe road salt off the outside trim to protect the finish.
What do backset and bore mean, and why does the locksmith ask?
Two measurements decide whether a deadbolt fits your door. Bore is the diameter of the big hole through the face, 54 mm on most current hardware. Backset is how far the centre of that hole sits from the door's edge, 60 mm or 70 mm on nearly all residential doors. A replacement must match both to use the existing holes, and a fresh installation is cut to match the knob below, so knowing them ahead puts the right hardware on the van.
Related services
- Lock Replacement & UpgradeThe house is fifteen years old and every exterior door still wears the light hardware the builder fitted: a short bolt, a thin strike held by two small screws, and a knob lock that never suited a street entrance.
- Vintage Mortise Lock ServiceThe old skeleton key still fits the keyhole, but it now needs a jiggle, a lean on the door and a little luck before the bolt moves.
- Smart Lock InstallationThe deadbolt is a stiff double-cylinder model that needs a key from both sides, and in the dark hallway finding it is a nuisance.