How to Rekey Commercial Door Lock

Rekeying a commercial door lock means changing the internal pins so old keys stop working, while the lock stays on the door. It is faster and cheaper than full replacement, and it solves the real problem: someone holds a key you no longer want them to have. Here is the process, plus the point where calling a locksmith beats doing it yourself.

Before You Start: Identify the Lock Type

You cannot rekey a lock until you know what you are holding. Commercial doors usually carry one of four types:

• Mortise locks. Heavy rectangular body set into a pocket in the door edge. Common on older office and retail entries.
• Cylindrical lever locks. Handle and cylinder pass through the door. The workhorse of schools, clinics, and offices.
• Interchangeable core (IC) locks. Figure eight shaped core that pulls out with a control key in seconds.
• Storefront cylinders. A mortise cylinder threaded into an aluminum glass door.

Check the cylinder face for a brand stamp. Schlage, Kwikset, Yale, Best, and Medeco use different keyway profiles, and your rekey kit must match exactly. A Schlage SC1 kit will not work on a Kwikset KW1 cylinder.

Also check for patented or restricted keyways. Medeco and Mul-T-Lock use sidebars and rotating pins that require factory authorization. Those are locksmith territory.

Tools and Materials You Will Need

• Rekey kit matched to your brand and keyway
• Plug follower sized to your cylinder
• Pin tray and pinning tweezers
• Flathead and Phillips screwdrivers
• Retaining ring pliers
• New keys cut to the new bitting
• Graphite or dry PTFE lubricant

Skip the follower and you will spray springs and top pins across the floor. It is a cheap tool that saves an hour on your knees.

Step by Step: How to Rekey a Commercial Door Lock

1. Remove the lock from the door. Back out the mounting screws, pull the lever assembly, and set the hardware on a clean flat surface. Photograph each stage. Reassembly is where most first timers get stuck.
2. Extract the cylinder. On a cylindrical lever lock, insert the old key, turn it about 15 degrees, and press the retainer to slide the plug out. On a mortise cylinder, loosen the set screw and unthread the cylinder counterclockwise.
3. Push the plug out with the follower. Keep the follower flush against the back of the plug so the top pins and springs stay trapped. Any gap and they drop.
4. Dump the old bottom pins. Tip the plug over a tray. You will not reuse them.
5. Insert the new key and pin the plug. Slide the new key fully in. Drop the correct bottom pin into each chamber until it sits flush with the plug. Run a straight edge across the top. Any pin sitting high or low is the wrong size, so swap it.
6. Reinsert the plug. Push it back in from the front, driving the follower out the back in one smooth motion. Do not let the plug rotate mid travel.
7. Test before it goes back on the door. Cycle the new key ten times, then confirm the old key does nothing. Only then reinstall and test the latch, strike alignment, and closer.

Budget 20 to 30 minutes for your first cylinder, and about 10 minutes each after that.

When to Call a Professional Locksmith

Bring in a licensed locksmith when:

• The cylinder is restricted or high security
• You need a master key system, where one key opens multiple doors at different access levels
• Fire code or insurance ties you to specific Grade 1 hardware
• The lock connects to access control, electric strikes, or panic hardware
• An employee left on bad terms and every exterior opening needs rekeying the same day

Master keying is not a DIY job. It uses master wafers stacked in each chamber, and a mistake creates ghost keys that open doors you never intended.

Choosing the Right Replacement Lock

If the lock body is worn, corroded, or older than 15 years, replace it instead. Three things decide the choice:

Grade. ANSI/BHMA Grade 1 is the commercial standard, tested to 800,000 cycles or more. Grade 2 suits low traffic interior doors. Grade 3 is residential and has no place on a business entry.

Function. Storeroom, classroom, office, and entry functions behave differently on egress and locking. Match the function to how staff actually use the door.

Code compliance. Exterior and stairwell doors need free egress at all times. Never install anything requiring a key to exit.

Measure backset, door thickness, and cross bore before ordering. A 2 3/4 inch backset lock will not fit a 2 3/8 inch prep.

Maintenance Tips After Installation

• Lubricate with graphite or dry PTFE twice a year. Oil based sprays attract grit.
• Tighten mounting screws quarterly. Loose hardware is the top cause of early lock failure.
• Check strike alignment whenever the door starts to drag.
• Replace worn keys before they break. A key you have to jiggle is already damaging the plug.
• Keep a written key log showing who holds what.

Why Buy from Auto Locksmith Boca

Auto Locksmith Boca stocks commercial cylinders, commercial locksmith kits, and Grade 1 hardware from brands that hold up, and every lock ships keyed to your specification. You get keyway matching help before you order, so you are not guessing between SC1 and KW1, plus same day service across Boca Raton. Call and describe your door first. Two minutes now prevents the wrong part arriving.

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