Master Key Systems

Adding master pins does create extra shear lines, so a master-keyed cylinder has more theoretically valid combinations than a straight-keyed one — that's a real trade-off, not a myth. The practical answer is design and hardware: a properly charted system keeps incidental combinations to a minimum, avoids the cross-keying that plagues improvised systems, and a restricted high-security cylinder like Mul-T-Lock remains extremely resistant to picking and bumping even when master keyed. The insecure version of master keying is the one done ad hoc over decades by whoever showed up — which is what most older NYC buildings actually have, and what a documented rebuild fixes.

Not necessarily the whole building — the answer depends on what his key opened, which is exactly what a keying chart tells you. If he held a building master, every cylinder that master operates needs re-pinning; apartment change keys can often stay valid, so tenants may not need new keys at all, which makes the job far less disruptive than it sounds. If the system was undocumented, we survey and decode what's actually in the doors first, then rebuild on a clean chart so the next departure is a scoped re-pin instead of a crisis. This is also the moment most owners move the masters to a restricted keyway, so the next ex-employee can't have quietly made copies beforehand.

Yes — NYC landlords routinely retain access for emergencies and repairs, and multiple-dwelling rules effectively require the owner to be able to get into units when it matters. What the master key does not change are the access rules: outside genuine emergencies, entry requires proper notice for repairs or inspections, and a tenant's own key must never open a neighbor's door. A designed system actually protects you here, because it eliminates accidental cross-keying and gives you a record showing exactly who was issued which key — useful the day a tenant claims someone entered their unit. If a tenant adds their own lock, that's a lease conversation, not a locksmith workaround we'll perform without the tenant's authorization.

On an open keyway, yes: any standard key, including a master, can be duplicated in a minute wherever blanks are sold, and there is no meaningful way to prevent it — 'do not duplicate' stamps are a suggestion, not a control. That's why we recommend building any system with real stakes on a restricted keyway. With Mul-T-Lock or Maxtek, blanks aren't available to hardware stores and every key is cut only for authorized signers against the system's record, so the count of existing keys is a fact you can verify rather than hope about. Many owners split the difference: restricted masters, standard change keys — the masters are the keys that can hurt you.

Yes, and in NYC it almost always has to — pre-war mortise cases, rim cylinders on jimmy-proof drop bolts, and modern cylindrical levers routinely coexist in the same building. As long as the cylinders run (or can be converted to run) a common keyway, they can all be pinned into one chart, and mortise, rim, and standard-profile cylinders are all available in that shared keyway, including the Mul-T-Lock restricted lines we stock. Where a cylinder is too worn or an obsolete format can't be sourced, we replace just that cylinder, not the visible hardware — important on brownstone and landmark doors where the original trim should stay. The survey stage exists precisely to catch these hardware realities before the chart is finalized.

A small building — say a three- or four-family brownstone — typically goes from survey to installed system within days: the chart is drafted after the walkthrough, and pinning plus installation is usually a single day on site since we pin in our own shop rather than sending cylinders out. Larger or restricted-keyway systems add hardware lead time, and we give you the real schedule at quote, not an optimistic one. Afterward, change keys and masters are cut against your keying record at 170 Hicks St or 232 Leonard St — standard keys promptly, restricted keys for authorized signers, generally same visit for common formats. Because we hold the records, a phone call with the key symbol is enough to have keys ready for pickup.