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Lock Cylinder and Keyway Guide

The cylinder is the part of the lock in which you insert the key.  There are different types of cylinders available. The most popular is the standard cylinder which can be identified by a single circle around the keyhole. (Check out our blog on standard cylinder keyways here.)

What is a Standard Cylinder? What is a Standard Cylinder Core?

Standard cylinder locks are best suited for those applications in which you do not want to change the keys to the lock frequently. They are cheap to buy, but repairing or changing lock keys will require a breakdown of the lock. In this case, the entire cylinder will have to be removed, and you will in all probability require a trained technician or locksmith to do it. Standard cylinders are manufacturer specific, so changing the cylinder for another manufacturers cylinder is not possible in most cases. Standard cylinders can be keyed alike or master keyed, so that the same key can be used on multiple locks.

Some cylinders have a removable or interchangeable core. This is identified by a figure eight shape around the keyhole.

What is an Interchangeable Core? What is an Interchangeable Lock Core?

The benefit of an interchangeable core is that if you want to change the key to the lock, only the core has to be removed. This is easily done without disassembling the lock. Even a non-technical person can change the core. Consequently, the locks with interchangeable cylinders are more expensive than the standard cylinders, but changing the key to the lock is simple, and saves time and money.

How to change the core of an interchangeable core lock?

An interchangeable core lock comes with a control key. Simply insert the control key into the lock, which releases a retainer that holds the core inside the lock, and the core slides out. Now insert the new core and lock it with the control key of the new core. The core is changed. No locksmiths and technicians are needed for this task. Even a non-technical person can change the keys to the lock.

Interchangeable core locks are more popular in commercial use, where frequency of changing cores can be high.

There are two main types of interchangeable cores:

    • Small size commonly called SFIC or small format interchangeable core. With SFIC cores, both the circles are of the same size. SFIC cores are more popular and cross compatible with cores of other manufacturers.
      Small Format Interchangeable Core Locks | SFIC locks
    • Large size commonly called as FSIC (full size interchangeable core) or LFIC (large format interchnageable core). With LFIC cores the upper circle is smaller than the lower circle.  LFIC’s are generally manufacturer specific.
      Large Format Interchangeable Core Locks | LFIC locks