Our most common jimmy proof deadbolt call is a pried rear door where the bolt held and the frame did not. A jimmy proof deadbolt is a surface-mounted vertical deadbolt: its bolts interlock with the strike, so door and frame cannot be pried apart. We install, replace and repair them across Washington DC, Maryland and Northern Virginia, licensed and insured.
A jimmy proof deadbolt mounts on the door’s inside face. Its case holds two vertical bolts that drop into rings on a surface strike on the frame. Key or thumbturn drives the bolts through those rings, so lock and strike interlock and a pry bar has nothing to spread. ANSI/BHMA A156.5, the add-on deadbolt standard, covers it.
The key works a rim cylinder, which passes through the door into the case. Most cases take a 1-1/8 inch rim cylinder in Schlage SC1 or Kwikset KW1 keyways, five pins each. Prep is one 1-1/2 inch hole at a 2-3/8 inch backset, no edge bore, suiting District of Columbia rowhouse rear doors.
The interlocking design is the benefit. A standard deadbolt throws a one-inch bolt into the frame, so a pry bar that spreads the frame that inch frees the door. A jimmy proof deadbolt locks door to strike, so spreading the frame moves nothing. On an outswing door, that keeps a burglar out.
Surface mounting fits doors that cannot take a fresh edge bore: old panel doors, thin doors, drilled metal doors. If your back door has only a knob latch, we install this upgrade first.
Across Maryland we install jimmy proof deadbolts on apartment entry doors, rowhouse rear and basement doors, garage side doors and small shop back doors. They are the standard add-on lock wherever a wood or hollow metal door meets a frame a pry bar could spread.
They are the wrong choice on a fire-rated door, where a surface-mounted lock voids the rating, and on narrow aluminum storefront doors, which take a hook-bolt deadlock. Unsure which lock fits? We survey it free.
Segal built the original jimmy proof deadbolt; its case, strike and thumbturn parts stay on our trucks, so the lock we quote most installs today.
Mag 8771 ships with a heavy steel case and reversible strike for left or right doors, so one unit from our stock covers any swing.
Marks USA cases accept most standard rim cylinders, the outside key unit, so we key a new deadbolt into the building's existing keyway same visit.
Kaba Ilco rim cylinders come in Schlage, Kwikset and Segal keyways, so when only the cylinder is worn, we replace it and leave the case.
Three failures fill our tickets. The bolts drop partway: the door has sagged, so the bolts land on the strike rings instead of through them. The key turns but the bolts stay put: the tailpiece, the flat bar carrying motion from cylinder to case, has sheared. The cylinder spins: the mounting plate screws have loosened.
Our locksmith checks door and strike alignment first, then cylinder mounting, then the tailpiece, because a sagging door mimics a broken lock. Locked out? We respond 24/7. Call (202) 800-2622 in Washington DC and NOVA or (240) 345-1455 in Maryland.
A sagging door gets a hinge reset from our in-house door expert, and we realign the strike. A sheared tailpiece means a new rim cylinder, pinned to your existing key. A spinning cylinder gets its mounting plate re-seated. Repair wins while the case is sound.
We recommend replacement after attack damage, discontinued cases, or when a double-cylinder unit traps occupants inside. We match hole size, backset, door hand and finish so the new case covers the old screw holes with no new drilling, and key the rim cylinder to your current key where the keyway allows. Measure, match, install, test throw and egress.
Jimmy proof deadbolts secure apartment entries, rowhouse rear doors, 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 Jimmy Proof Deadbolts questions customers ask us most.
(240) 345-1455
ANSI/BHMA A156.5, the auxiliary lock standard for add-on deadbolts.
A standard bolt enters the frame; jimmy proof bolts drop into a strike and interlock.
A thumbturn model does: anyone inside exits keyless. Double-cylinder models fit only where code allows.
