Mailbox locks are small key-operated locks that keep your mail private by holding the compartment door shut until your own key turns it. The call we get most: “I lost my mailbox key and the manager says it is on me.” King Locksmiths repairs, replaces and installs mailbox locks across Maryland, Washington DC and Northern Virginia. licensed, insured and bonded for 25 years.
Locksmiths call it a cam lock: a short cylinder with a flat arm on the back, the cam, that swings behind the frame as your key turns. The body sits in a flat-edged hole that stops it spinning, and a retaining nut clamps it from inside. In the plug, where the key enters, disc or pin tumblers line up only for your key.
Body length, cam length and cam offset decide whether the door catches, so we measure the old lock first. The same format fits mail banks, wall units and 4C units, the postal standard in newer buildings, so our trucks carry common body lengths, cams and keyed-different cylinders.
Only your key opens your compartment, so statements, checks and replacement cards stay out of a stranger’s hands. Most mailbox locks are key retaining: the key will not come out until the door is locked, so nobody walks away leaving the door open.
Because the body fits the standard flat-sided hole, a worn or keyless lock is swapped in minutes without touching the door. Every replacement arrives keyed different, so your new key matches no neighbor’s. When the key is gone, replacement is the decision.
We replace mailbox locks on apartment lobby mail banks, condo wall units, privately owned cluster boxes and office mail rooms across Northern Virginia, for the tenant who lost a key and the manager turning over a unit.
Two cases are the wrong fit. The carrier’s master lock belongs to the postal service and we never open it, and tenant locks on a cluster box the postal service owns are handled at the post office. Unsure who owns yours? Ask us.
Tell us which unit you have, a lobby bank, wall unit or cluster box, and we bring the matching mailbox lock and fresh keys today.
5 brands earned their place on our trucks for mailbox work: cylinders we stock, cams that match, keys cut fresh, doors that catch every close.
National C8700 is the mailbox lock most apartment banks were built with; we stock its cylinders and cams, so your compartment is secured same visit.
ESP ULM locks ship with several cams, the arm that catches behind the frame, so one cylinder fits units whose maker discontinued the original part.
Hudson mailbox locks carry a stamped key code, so a property manager tracks which key opens which compartment and orders exact replacements from us later.
Florence replacement locks fit 4C wall units, the postal standard in newer buildings, so a lobby built to that standard gets its exact matching part.
Three problems bring most calls. The lock spins and the key will not catch: the retaining nut has loosened or the hole’s flat edge has worn round. The key is lost or left with a tenant: only a keyed-different cylinder kills the old key. The key will not turn on an exterior unit: corrosion has seized the tumblers in the plug.
We confirm who owns the unit, then check nut, cam and plug before quoting. Locked out after hours? We respond 24/7. Call (240) 345-1455 in Maryland or (202) 800-2622 in Washington DC and NOVA.
A spinning lock is fixed by tightening the retaining nut or adding an anti-rotation washer, a flat washer that grips the worn hole. A seized exterior lock is flushed, lubricated and worked free; a broken key comes out with an extractor. A lost key is the exception: a mailbox cylinder costs less than the labor to rekey it, so we replace it.
For replacement we measure body length, cam length and offset, fit a matching key-retaining cylinder with a new nut, and check the door catches. You receive two fresh keys; managers get the key code logged. Measure, match, install, test: one visit. Free estimates.
An open or keyless mailbox is an identity risk, not a maintenance ticket. Call (240) 345-1455 now or book mailbox lock service online today.
Mailbox locks secure tenant compartments and shared parcel lockers, but every door has its match. Browse our lock type resources below to see each function, its applications and our services.
Straight answers from King Locksmith Technicans to on Mailbox Locks questions customers ask us most.
(240) 345-1455
Usually yes, so a lost key means a new lock: key counters cut mailbox blanks.
The owner or manager, and we do the work. The carrier’s lock stays with the postal service.
Almost always: mailbox locks share one standard body and hole; we match the cam.
No, mailbox cylinders take small blanks, not door keyways, so it stays separate.
