High-Security Lock Installation NYC — Medeco & Mul-T-Lock
A high-security lock buys you two things a standard lock cannot: keys that cannot be copied behind your back, and a cylinder built to shrug off attack attempts. This spring we installed a Mul-T-Lock high-security cylinder on an apartment door and upgraded the lock on a glass entry door in a modern residential building — both jobs photographed on our recent jobs page. Sunny Locksmith installs Medeco M4 and Mul-T-Lock MT5+ hardware across NYC under License #2096389-DCA. Call (917) 495-1990.
What "High-Security" Actually Means
Marketing has worn the phrase out, so here is the working definition we use: a high-security lock has a restricted keyway, so blank keys are not sold to the public and copies require your authorization card at a licensed dealer; and it has a UL 437 rated cylinder, so attacking it takes tools and time a burglar does not have. Medeco M4 and Mul-T-Lock MT5+ meet both tests. A bargain "heavy duty" deadbolt from the hardware store meets neither.
Key Control Is the Real Product
Most break-ins into NYC apartments do not involve any fancy technique — they involve a key that should not exist. A former roommate, an ex, a contractor, a previous tenant. With a restricted keyway, every key in circulation is one you personally authorized. That is what the Mul-T-Lock installation we did this spring bought the client: not just a stronger cylinder, but a complete accounting of who can open the door.
Medeco M4 vs. Mul-T-Lock MT5+
We install both weekly, and the honest difference is small. Medeco M4 pins rotate as well as lift, and it holds up famously against drilling. Mul-T-Lock MT5+ uses telescoping pin-in-pin technology plus a slider element. Both have restricted keyways. Our advice usually comes down to the door: what fits the existing prep, what the building keyway situation is, and which dealer network is more convenient for your future key copies.
Installation on Real New York Doors
Pre-War and Mortise Doors
You do not need to replace a beautiful pre-war mortise lock to get high security. We fit MT5+ and Medeco cylinders into existing mortise bodies — the door keeps its hundred-year-old face, the lock gets a modern brain. We do this on Upper West Side and Brooklyn Heights doors constantly; recent mortise work from 72nd St & Broadway and Sunset Park is on our work page.
Custom and Oversized Doors
Custom and oversized doors are often the kind where standard backsets and strike plates simply do not fit. We source extended backset latches and custom strikes, and we match finishes (oil-rubbed bronze, satin nickel, polished brass) so the security upgrade does not fight the interior design.
The Frame Matters as Much as the Cylinder
A pick-proof cylinder on a kickable frame is security theater. Every high-security install we do includes a look at the strike side: heavy-duty strike plate, 3-inch screws into the stud, and on vulnerable doors a latch guard so the bolt cannot be attacked with a bar. If the door itself is the weak point, we say so before you spend money on the cylinder.
Who Actually Needs This
Honest answer: not everyone. If you are worried about a specific person with a key — get a restricted keyway, it is built for exactly that. If your building has had break-ins through the door, get the UL 437 cylinder plus frame reinforcement. If your threat model is a lost key once a decade, a quality Grade 1 deadbolt and a rekey will serve you fine, and we will tell you so. Businesses with staff turnover should look at restricted-keyway systems across all doors — see commercial high-security locks.
Frequently Asked Questions
Can you put a high-security cylinder in my existing lock?
Very often, yes. Medeco and Mul-T-Lock make cylinders in mortise, rim, and standard key-in-knob formats, so we can usually upgrade the cylinder and keep your existing hardware — including pre-war mortise bodies, which keep their original look.
Can someone copy a Medeco or Mul-T-Lock key at a hardware store?
No. The keyways are restricted: blanks are not sold to the public, and copies require your authorization card at a licensed dealer. That is the main reason to buy these locks — every key in circulation is one you approved.
Are high-security locks worth it for a rental apartment?
If you are worried about who holds copies of your key — a previous tenant, an ex, building staff — yes, and a restricted keyway solves exactly that. Check your lease first; we regularly coordinate with landlords and supers so the install does not violate building rules.
Whats the difference between this and a regular Grade 1 deadbolt?
A Grade 1 deadbolt resists force well but its keys can be copied anywhere and its cylinder can be picked or drilled with common tools. High-security cylinders add restricted key control and UL 437 attack resistance. Many of our installs combine both: Grade 1 hardware with a Medeco or Mul-T-Lock cylinder inside.
