Rekeying gets quoted, booked and paid for constantly by people who have never been told what it does. The word sounds like it might mean a new lock, or a new key cut from the old one, or something the hardware store does at the counter. It is none of those. Rekeying is a change made to the small stack of loose parts sitting inside the cylinder you already own, and once you can picture those parts the whole subject stops being mysterious — including the two questions that matter most, which are whether your particular locks can be rekeyed at all and whether rekeying them is the right answer instead of replacing them.
Talk it through first · (850) 726-4791Take a standard residential deadbolt. The part your key slides into is a cylinder, and the cylinder has two main pieces. The outer piece is fixed — call it the shell or housing — and it does not move when the key turns. Nested inside it is the plug, a rotating core with the keyway machined down its length. Turning the plug is what retracts or throws the bolt. Everything a lock does mechanically comes down to whether the plug is free to rotate or not.
Drilled down through the shell and into the plug is a row of chambers, normally five or six of them, sitting in a line above the keyway. Each chamber contains three things stacked on top of each other. At the bottom, resting where the key will reach it, is a key pin. Above that is a driver pin. Above that is a small coil spring pressing the whole stack downward.
The critical detail is the boundary between the rotating plug and the fixed shell. That circular seam is the shear line. With nothing in the keyway, the springs shove each stack down so that every driver pin sits half in the plug and half in the shell, straddling the shear line. Each of those pins is a bar bridging a moving part to a stationary one. The plug cannot rotate, and it does not matter how hard you turn.
The jagged edge of a key is not decoration and it is not a serial number. Each notch is a height. As the blade slides into the keyway, every cut passes under its own chamber and lifts that stack by however much that cut is deep or shallow.
A correct key lifts every stack by exactly the right amount to put the joint between the key pin and the driver pin level with the shear line — all of them, simultaneously. The instant that happens, no pin is bridging the seam any more. The plug is free, it rotates, the bolt moves. A wrong key lifts the stacks to the wrong heights: some pins are still crossing the shear line, others have been pushed too far and are crossing it from the other side. Either way something is in the way and the plug will not turn. That is the entire mechanism, and every rekey question is downstream of it.
Rekeying replaces the bottom row — the key pins — with a set of different heights. Nothing else about the lock changes. Same body, same bolt, same finish, same screws, same strike plate, same hole in the door. The lock is not removed from your life, it is not swapped for a different model, and from the outside it is indistinguishable from the lock that was there this morning.
Because the key pins are the pieces the key actually touches, changing their heights changes which pattern of cuts can align the stacks at the shear line. A new key is cut to match the new pin heights and it works. The old key still slides in perfectly — the keyway did not change — but it now lifts every stack to a height that no longer produces a clean shear line. It turns nothing.
This is the part worth understanding, because it answers the question people are usually really asking. There is no grace period, no phased retirement, no window in which both keys work. The moment the technician reassembles that cylinder and hands you the new key, every copy of the old key in existence is a piece of scrap metal, wherever it is and whoever is holding it. You do not have to find them, count them, or ask for them back. That is the whole product.
Two things separate a rekey that lasts from one that starts sticking. The first is precision in pin selection: pin heights come in fixed increments, and a stack that is one increment off will still turn a healthy lock while quietly relying on slack that will not be there in a year. The second is the springs. Springs that have been compressed inside an exterior door for a decade — especially near the water, where humid salt air reaches into the chambers — do not spring the way they did. Replacing them while the plug is already out costs almost nothing and prevents the call where a freshly rekeyed lock has started to bind.
The test is whether the piece that reads the key is a serviceable assembly of separate parts. If it is, it can be rekeyed. If it is sealed, moulded, or worn out of tolerance, it cannot — or it can, pointlessly.
One case straddles the line: a lock with no working key at all. Every mechanism above remains rekeyable in principle, but the plug has to be rotated to the shear line before it can leave the shell, and with no key that means the lock must first be opened some other way. That is a materially different piece of work than a routine rekey, and it is why two rekey jobs on identical hardware can be nothing like each other.
Rekey when the hardware is fine and the key situation is the problem. Replace when the hardware itself is the problem.
Key-situation problems: a house that just changed hands, a departed tenant, a key that went missing, a contractor who may have kept a copy, three doors that each need their own key when one would do. In every one of those the lock is doing its job perfectly; the only thing wrong is who can operate it. New pins fix that completely.
Hardware problems: a cylinder that rocks in its hole, corrosion visible down the keyway, a bolt that no longer extends its full throw, a knob that turns while the lock is engaged, a latch that no longer catches because the door has settled in its frame. New pins fix none of that. A rekey on failing hardware is a bill for a problem you did not have.
Two more situations push toward replacement even when the locks work. One is standardising a property whose doors use incompatible keyways, where getting everything onto one key requires matching cylinders regardless. The other is a security upgrade you were going to make anyway — a heavier bolt, a reinforced strike, better-graded hardware. Re-pinning parts you have already decided to retire spends the money twice.
Pinning several cylinders to the same bitting is called keying alike, and it is the request people most often make without knowing its name. It works whenever the cylinders accept the same key blade — the blade has to physically enter each lock before its cuts are relevant. When the keyways are incompatible, no amount of clever pinning bridges them and the odd cylinders have to be changed for ones that match. Photographing each key flat, and photographing straight into each keyway, usually settles the question before anyone drives out.
Be deliberate about it, though. One key for everything means every copy of that key opens everything, and if it is lost the entire property gets rekeyed rather than one door. Plenty of households keep the main entry on the shared key and deliberately leave a shed, a gate or an interior office door on its own bitting for exactly that reason.
A master keyed system lets one key open every door while each individual key opens only its own. Mechanically that is done by inserting an extra flat piece — a master wafer — into some chambers, between the key pin and the driver pin. That wafer creates a second position in the stack where a gap can arrive at the shear line, so two different cut depths satisfy that chamber rather than one.
Here is the honest cost. Every chamber that gets a master wafer multiplies the number of key patterns that will rotate that plug, and those extra patterns are not keys anyone chose to create — they are simply cuts the geometry now tolerates. Stack up additional levels of hierarchy and the count grows again. So a master keyed cylinder is measurably easier to defeat than the same cylinder pinned to one key, and a sprawling system laid out without a plan can end up accepting far more keys than its owner would guess.
Against that: a building where one person can reach every room without a belt of forty keys is drastically easier to run, and manageability is a genuine security property in its own right. The rule of thumb is to master key where a real hierarchy exists — multiple tenants, a commercial suite, staff with different levels of access — and to design it once, on paper, before any pinning happens. For a house with three exterior doors there is no hierarchy to express, and keying alike delivers the same convenience with none of the compromise.
Rekeying answers exactly one question: who currently holds a key that turns this lock. It is worth doing whenever the honest answer to that question is "no idea."
A house under construction has an unavoidable key problem — framers, electricians, plumbers, painters and inspectors all need entry for months before any owner exists. There are two ways builders handle it and they are not equally trustworthy.
The good way is hardware with a construction keying feature built in. Additional elements are staged inside the pin chambers so a builder key runs the lock through the build. The first time the owner's key is inserted and turned, those staged elements are permanently displaced — a small pin shears away, or a ball bearing drops clear — and the builder key stops working from that instant, with nothing to disassemble and nobody to trust. If your builder tells you the locks have this, turning your own key in every exterior door on the first day is the action that activates it. Do it before you start carrying boxes in.
The ordinary way, far more common on residential builds, is that somebody cut a stack of copies of one key and handed them out. Those copies are not logged, they do not expire and they do not return.
So the sensible default for a new build is identical to the default for a resale: assume unknown copies are out there and rekey. It is one of the few items on a closing checklist that takes well under an hour and leaves no mark on hardware you have just paid for.
Rekey jobs go sideways over information that existed and never got mentioned. Cover these and a vague estimate becomes a firm one.
The pinning itself is the quick part. With a cylinder out and open on a working surface, exchanging a set of key pins and proving the new key is short, careful, repetitive work — minutes for a standard residential cylinder, not hours.
What actually drives the total is everything around it. Extracting a cylinder from a mortise case takes longer than backing a deadbolt out of a bored door. A cylinder that has spent a decade in humid coastal air may need cleaning and new springs before it is worth pinning at all. Mixed keyways mean some cylinders get replaced rather than re-pinned. Keying alike means no door can be signed off until every cylinder is finished, because they all have to answer to one key. And each door gets properly tested at the end — key in and out, bolt thrown and withdrawn, first with the door standing open and then again closed against the frame, because a bolt that behaves on an open door and drags on a closed one is a strike alignment problem, and finding it while the tools are still out is the right time to find it.
A house with a handful of healthy matching cylinders and keys in hand is a short visit. The same house with one seized cylinder, two incompatible keyways and a garage door nobody has a key for takes most of a morning. Both get described on the phone as "a rekey", which is exactly why the details above are worth having in front of you when you call.
Yes, the moment the cylinder is reassembled. There is no overlap period. The old key still fits the keyway but no longer lifts the pins to the shear line, so it turns nothing.
Usually. A cylinder can be pinned to match a key you already carry instead of a newly cut one, provided that key fits the keyway. Say so before the work begins.
Against someone holding an old key, yes — that key is dead either way. Rekeying does not change how the lock resists force, though. If forced entry is the worry, the answer is better-graded hardware and a reinforced strike plate, not new pins.
Often, but it is a different job. The plug has to be rotated before it can come out, so the lock has to be opened first. Flag it when you call rather than at the door.
No. Changing codes retires numbers. If the lock also has a keyed override cylinder, that cylinder is untouched and any old physical key still works it. Both need dealing with.
Yes. Shalimar Locksmith is a licensed, insured, owner-operated mobile locksmith working in Shalimar, FL.
Not sure whether your doors need rekeying, re-pinning to a key you already own, or new cylinders altogether? Describe what you are looking at over the phone before anything is booked. Shalimar Locksmith is mobile and owner-operated, working in Shalimar, FL.