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Master keying sounds like something for hospitals and campuses, but the same idea works for a shop with an office, a stockroom and a back door. Schlage's training material notes that master keying reduces the number of keys people have to carry.
This guide explains the levels in a system, how to plan one, the cylinder choices that matter, and the key-control habits that keep it working. For setup on your own doors, see our commercial locksmith service.
How a master key system works
Each lock is pinned so it opens with two (or more) different keys: the key for that door and a key higher up the chain. The higher key is cut to work with every lock in its group.
| Key level | Who typically holds it | Opens |
|---|---|---|
| Change key | An employee or tenant | One door or one group of identical locks |
| Master key | A manager or department lead | Every lock in one group, such as all offices |
| Grand master key | The owner | Every lock across all groups |
| Separate (non-master) key | Whoever needs that space only | A lock kept out of the system on purpose, such as a cash room |
Small businesses rarely need more than two levels. Every extra level adds complexity to the pinning and the records.
Planning the system
Start with a floor plan and a list of people, not with hardware.
- List every door with a lock, including closets, gates and cabinets with cylinders.
- Group the doors by who needs them: front of house, back of house, offices, storage.
- Match people to groups. Most staff need one or two groups, not everything.
- Mark the sensitive openings. Schlage advises choosing security levels based on your most sensitive or at-risk openings, since those shape the approach everywhere else.
- Decide on growth. If you expect to add a suite or a second location, plan for it now.
Cylinder choices: conventional vs. interchangeable core
Schlage describes two broad options for commercial cylinders:
- Conventional cylinders are more secure but usually need some lock disassembly to rekey.
- Interchangeable cores (IC) can be removed directly from the lock, which makes rekeying faster. Schlage notes that because they're designed to be removable, they are less secure than conventional cylinders.
- SFIC (small format IC) is a standardized shape, typically 7-pin, interchangeable from one manufacturer to another.
- FSIC (full size IC), also called LFIC, typically uses 6 pins and can share keyways with conventional cylinders.
Schlage's key-control guide suggests interchangeable cores for businesses with high employee turnover, so a lost key can be dealt with quickly without removing the lock.
Key control: the part most businesses skip
Schlage's key-control guide puts it simply: locks only limit access to a building if you control the keys that operate them. A master key system without records is just a fancier pile of keys.
- Number every key and record who holds it, with a signature.
- Collect keys at exit as part of offboarding, the same as a laptop.
- Limit who holds masters. The fewer copies, the smaller the risk.
- Use restricted keyways for the system. Per Schlage, blanks for a restricted keyway come only through the maker's channels, and buyers such as locksmiths or facility managers must open an account and show they're authorized.
Schlage notes that losing a master or perimeter key can force a complete or partial rekeying of the building. Treat master keys like cash: tracked, signed for and never lent out.
Patents and restricted keys
Restricted and patented keyways make unauthorized copies harder. Schlage notes that if a restricted keyway's patent has expired, aftermarket manufacturers can still make its keys. Ask when the patent on a keyway runs out before building a system around it.
California law also helps. California's B&P 6980.54 stops licensed locksmiths from copying restricted or high-security keys that carry the issuing company's name together with its phone or registration number. Our guide on keys that can't be copied explains more.
Next steps
If you already have a pile of mismatched keys, a master key project often starts with a rekey of the existing locks into the new plan, replacing only the hardware that can't be pinned into the system.
For a walk-through of your doors and a key plan, contact our business locksmith team at (562) 534-1992. The tech reviews the plan and its price with you before any locks are touched.
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Frequently asked questions
Is a master key system worth it for a small office?
If more than a few people need different access, usually yes. It cuts the number of keys people carry and lets you control who opens which door.
Does a master key make my locks less secure?
Master keying adds a second key that opens each lock, so key control matters more. Restricted keyways and good records keep that risk low.
What happens if an employee loses a master key?
Every door that master opens is now at risk. According to Schlage, a lost master can mean rekeying part or all of the building, so keep the number of masters small and log who holds them.
Can I add doors to the system later?
Usually, if the system was planned with room to grow. Tell the locksmith about likely expansions when the system is first designed.
