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How To Construction Key A Lock

Construction keying is a powerful skill that can be offered to customers when their home or office is being worked on or serviced by construction, cleaning, or other short time personnel. The values of this service can be forgotten or unknown by some lock professionals not accustomed to the practice of construction keying. A keen locksmith arriving on a job site or noticing short term workers can inform their client of the value added services available through construction keying.

What Is Construction Keying?

construction keying balls

Construction keying is the process of keying a lock cylinder with a small, round metal insert that is used as a temporary master pin. A construction key is cut with a depth deeper than the owner/tenant key. When the shallower depth of an owner/tenant key is inserted and turned, the round insert falls into the slot cut in the lock plug. These holes or “pockets” are usually seen a few degrees off from the primary pin chambers in a lock plug.

Benefits Of Construction Keying

This process is useful because it allows the temporary access to a worker without a home/business owner giving away the key to the residence. After the owner/tenant key is inserted and turned in the lock, the temporary key is locked out and will no longer work.

Construction Keying Explained

lock plug

Construction keying capable plug with side ports for construction ball exit.

To construction key a lock, first identify the brand and plug are capable of accepting a construction keying, as well as the availability of construction keying inserts. These bearing-like, metal balls are often equal to a number two or three master pin size. After this is verified, a construction and owner/tenant key will need to be cut. The existing key can be used for the owner/tenant key by cutting to code a construction key with a deeper depth in one of the chambers.

An example of this may be:

Owner key- 2 4 5 7 9
Construction key – 5 4 5 7 9

Therefore the keying would be:

2 4 5 7 9

– * represents a construction ball insert replicating a “3” master pin

The construction insert is placed in the chamber in the same way a master pin would be used when keying. Often, three construction keying balls/inserts are used per chamber. As can be seen on the above photo, many lock plugs do not have construction keying chambers available for each primary pin chamber.

Once inserted, it acts as a temporary master pin. As soon as the owner key is inserted and turned, the construction key will be locked out. The construction ball insert rests in the side pocket or chamber in the lock plug until another rekey is done in the future.

Necessary Locksmith Tools and Supplies

All of the general rekeying tools will be necessary when construction keying a lock. A multi-pick tool, c-clip remover, kwikset removal tool, lock plug follower, screw driver, and lock shims are all tools to have available depending on the type of lock being serviced. A code machine, space and depth keys, or key punch will be needed to create the construction key. Lock bottom pins will be needed to replace the existing lock pins if the original key is being changed. Lastly, a package of construction inserts serve as the crucial piece.

This process can be a great help to customers using temporary workers. The convenience and peace of mind can be a great selling point to locksmiths looking to offer this service. Even a simple conversation at the job site can inform a customer of this service. A customer may not need the service at the moment, but a future time may likely arise when a construction key is needed.

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