Before you decide what to do about a lock, it helps to know what is inside it. This page explains pin-tumbler locks, why rekeying makes old keys useless, what the grade stamped on a deadbolt box means, why a keyway matters, how bumping and picking work and what resists them, how smart locks fail, and the difference between the chip in your car key and the fob in your pocket. Written by working locksmiths in Pensacola. When you need one, call (850) 740-4626.
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This is a reference page. There are no sales pitches in it, just the mechanics of the locks on your doors and cars explained the way we would explain them at your kitchen table in East Hill or leaning on the hood in a parking lot on Navy Boulevard. If a section raises a question about your own locks, call (850) 740-4626 and we will look at them in person.
Nearly every keyed lock on a Pensacola house is a pin-tumbler lock. Inside the cylinder is a rotating plug surrounded by a fixed housing. Drilled across both, usually five or six chambers, are stacks of pins: a bottom key pin that touches the key, a top driver pin above it, and a spring pushing both down. With no key, the driver pins straddle the line between plug and housing, the shear line, and the plug cannot turn.
The cuts on the key lift each pin stack by an exact amount. The correct key lifts every stack so the gap between key pin and driver pin lands precisely at the shear line. Nothing is straddling it, the plug rotates, and the cam on the back of the plug throws the bolt. The wrong key lifts at least one stack too high or too low, a pin crosses the shear line, and the plug binds.
Brass keys wear with every insertion. Over years the cuts get shallower and rounder, the pins sit slightly off, and the lock gets fussy. Copying a worn key copies its errors and adds a little more. This is why a key cut to the original code turns smoothly when the fourth-generation copy has to be jiggled.
Rekeying is nothing more than replacing the key pins with pins of different lengths that match a different key. The cylinder, the bolt, the trim and the strike stay put. Because the old key now lifts every stack to the wrong height, it is useless. Every copy of it anywhere in Pensacola is useless. This is why rekeying is the right answer after a move, a lost key, a roommate change or a contractor who had access.
If two locks share a keyway, we can pin both to the same key. That is keying alike, and it is why a house with four exterior doors can run on one key. Locks with different keyways cannot be keyed alike without replacing one cylinder.
A master key system adds a second, thin pin to some chambers so that two different keys each create a shear line: the change key for one lock and the master for all of them. Landlords with a fourplex in Brent, or a homeowner with a rear apartment in North Hill, use this constantly. The trade-off is that every extra master pin adds another combination that opens the lock, so master systems are designed carefully rather than stacked casually.
The number on the deadbolt box is an ANSI/BHMA grade, and it is the single most useful thing printed there. The tests measure cycles, bolt strength, impact resistance and how the lock survives being struck, pulled and twisted.
Commercial grade. Tested to a million cycles and the heaviest strike and pull loads. On a house it is reasonable for a main entry, a door facing an alley, or a home office holding equipment. Most people do not need it on every door.
Heavy residential and light commercial. Several hundred thousand cycles and solid impact numbers. This is what we usually recommend for front and rear doors in Pensacola, and it is where the well-made residential deadbolts sit.
Basic residential. It meets minimum standards and not much more. It is what builders install because it is cheapest. If the deadbolt on your front door has no grade on it at all, treat it as below Grade 3.
A Grade 1 deadbolt in a strike plate held by two short screws into a soft pine jamb is only as strong as the jamb. The bolt, the strike, the screws and the door all have to hold. We look at all four before recommending a grade.
A keyway is the profile of the slot the key enters, the wavy shape you see looking at the end of a key. Manufacturers use different keyways, and within a manufacturer there are usually several. A key will not enter a lock with a different keyway no matter how it is cut. Keyways decide three things: whether a given blank fits, whether two locks can be keyed alike, and how easy it is for someone to buy a blank and copy your key.
Common residential keyways use blanks sold everywhere, so anyone with your key can copy it at a kiosk. Restricted keyways use blanks that are only available through authorized locksmiths and require proof of ownership to duplicate. For a rental owner in Pensacola tired of tenants making copies, a restricted keyway solves the problem at the root.
Picking uses a tension tool to apply slight rotation to the plug and a pick to set the pins one by one at the shear line. Bumping uses a key cut to the deepest position in every chamber, inserted one notch short, and struck so the driver pins jump above the shear line for an instant while the plug turns. Both defeat basic pin-tumbler locks. Neither is common in actual Pensacola burglaries, which are overwhelmingly kicked doors and unlocked doors, but both are worth understanding.
Security pins: spool pins and serrated pins that give false feedback and bind at the wrong point. Tight manufacturing tolerances so the pins do not set one at a time. Sidebars that require a second element of the key to line up. High-security cylinders combine all three.
Security pins help. Cylinders with a sidebar or a sliding element that a bump key cannot activate help more. Some manufacturers offer bump-resistant pin stacks that can be installed in an existing cylinder during a rekey, which is the cheapest upgrade available.
For a house in Ferry Pass or Cordova Park, the order of importance is: lock every door, reinforce the strike with long screws, put a real deadbolt on every exterior door, pin the sliding door, and only then worry about pick and bump resistance. Most break-ins never touch the pins.
Electronic locks fail in predictable ways, and knowing them ahead of time separates a minor inconvenience from a lockout.
The most common failure by far. Heat drains batteries faster, and a west-facing door in a Pensacola August is hot. Most locks warn for weeks before dying; people ignore the warning. Change batteries every spring and fall regardless.
Wi-Fi and Bluetooth locks lose connection when the router is too far away or the door is metal. The lock still works from its keypad; only the remote features drop. A bridge or a closer access point fixes it.
The motor that throws the bolt is a wear part. If the door is misaligned and the bolt drags on the strike, the motor works harder every cycle and fails early. Aligning the door and strike is the fix, and it is usually the reason a lock that worked for a year begins to stall.
A lock tied to an app can be locked out by a forgotten password, a changed phone, or a manufacturer outage. The mechanical key override exists for exactly this, and it should be tested once a season and stored somewhere other than inside the house.
Keypads on the bayou and beach side of Pensacola corrode at the contacts. Sealed capacitive keypads outlast rubber-button pads in that environment.
Since the late 1990s most cars carry an immobilizer. The key or fob has to identify itself electronically or the engine will crank without starting. There are two families.
A glass or carbon chip sits in the plastic head of a metal key. When the key is in the ignition, a coil around the ignition powers the chip by induction and reads its code. No battery in the chip. A mechanical copy of the blade opens the door and turns the cylinder but will not start the car until the chip is programmed.
The fob has its own battery and a radio transmitter. The car pings for it when you touch the handle or press the start button. The blade, if there is one, is an emergency backup hidden inside. Programming a proximity fob usually needs a diagnostic-port session with the vehicle and sometimes a manufacturer security code.
Neither is inherently better. Proximity systems are vulnerable to relay attacks that extend the fob's signal from inside the house to the driveway; transponders are not. Transponder keys can be cloned if the chip type allows it; most modern proximity fobs cannot. Storing a proximity fob in a signal-blocking pouch at night removes the relay risk.
Bolt: the part that extends from the lock into the door frame. Cylinder: the housing and plug assembly that holds the pins and accepts the key. Deadbolt: a bolt with no spring, thrown and retracted only by key or thumbturn. Latch: a spring-loaded bolt that retracts when the door closes; found in knobs and levers. Strike plate: the metal plate on the frame the bolt enters. Shear line: the gap between plug and housing where pins must align for the plug to turn. Key pin: the lower pin that touches the key. Driver pin: the upper pin pushed by the spring. Keyway: the profile of the key slot. Blank: an uncut key of a given keyway. Bitting: the pattern of cuts on a key. Code: the number that specifies a key's bitting. Rekey: repinning a cylinder to a new key. Keyed alike: multiple locks pinned to one key. Master key: one key that opens a set of locks that also have individual keys. Restricted keyway: a keyway whose blanks are controlled by the manufacturer. Security pin: a spool or serrated pin that resists picking. Sidebar: a secondary locking element requiring a matching feature on the key. Immobilizer: the vehicle system that prevents starting without a recognized key. Transponder: the passive chip in a car key. Proximity fob: an active radio key for push-button-start cars. Origination: making a key when none exists. Extraction: removing a broken key from a lock.
If you read this far, you know more about locks than most of the people selling them. When you want that knowledge applied to your own doors anywhere in Pensacola or Escambia County, call (850) 740-4626.