The skinny on interchangeable core locks: any person with a special key can change an SFIC-compatible or “Best” lock in seconds. They would do this with a special key by removing a “core” from the lock and then adding a different core to the lock, the core being the part you put your key into. The cores accept different keys. The advantage here is that if your restaurant fires an employee with violent tendencies or a criminal record and you suspect they have access to a key, for example, you can change the locks immediately when they leave. No need to call a locksmith.
Scenario two: you have an apartment building with twelve units. Somebody obtained your master key and can now enter anybody’s apartment, and you may be liable for damages if that person uses that key for their own nefarious ends. What do you do? Calling a locksmith and having all of the locks rekeyed is an option, but if it is late at night expect to pay a lot of money, and it might take a few hours or three. You lose lots of time and lots of money.
But what if you could get a bag of locks out of your safe and go rekey all twelve of the locks by yourself in twenty minutes? The bag of locks from your safe uses a different master key so you are covered. Whoever has the old master key is now holding a key that doesn’t open anything at all!
The main advantage of SFIC locks are that it is really fast and easy for the owner or manager to change locks in the event a key is compromised, but it is also very difficult for somebody to figure out what the master key is for the building. You can’t remove an SFIC core without:
- Having the control key
- Being good at lockpicking, or
- Being good with an angle grinder or some other destructive method of entry,
…and you can’t take the pins out of the core unless you take the core out first. If somebody drills the core out they will probably damage the pins and it will be difficult to eject the pins anyway and keep them in order with a mangled core.
SFIC locks are therefore very secure and inexpensive in the long run. If they are properly installed once, they need not be removed from the door again. The core can be removed or added hundreds of times. You can have two or three backup sets of cores, all keyed up to different master keys. Or you can have one huge bag of cores all keyed up to one master key and swap out cores as people move in and out of your building. When all of the cores have been used you can bring them all to me or any other locksmith once every few years to have them rekeyed (unless you want my CX5 cores, with restrictive keys. Then you have to bring them back to me). You never have to pay a locksmith to come to your building ever again. Actually, if you use CX5 cores and tenants return all of their keys you don’t have to rekey their locks at all because you know that they don’t have any key copies since the keyway is restricted.
To go back to the apartment building scenario, what are the real world costs? An SFIC-compatible deadbolt starts at $45 without core. If your apartments have one deadbolt and a passage knob we can leave the knob and swap out the deadbolt for an SFIC deadbolt. That is twelve SFIC deadbolts. You probably want fifteen or twenty cores to account for changes in renters, so your cost for me to come install this sort of system would be:
- Service call: $75
- 12 SFIC deadbolts: 12*$45=540
- 15 SFIC cores: 15*$35=525
- Labor charge of $120
- Keys at $3 each
- Masterkey system design for free
Your total cost to have new locks that you can rekey yourself in thirty seconds: $1493. This sounds like a tremendous amount of money until you remember that after this initial outlay, there are virtually no more costs to you. This system begins paying for itself after 17 tenant changes, assuming you pay $85 every time somebody comes out and rekeys a lock. It also gives you the ability to immediately change your building’s locks.
I am also a dealer of CX5 SFIC cores. These are just like regular Best cores, but also use restricted keys and a sidebar, making it very difficult to pick the lock to open the door or remove the core. If you buy these you know that you are the only one who can get duplicate keys. If somebody loses a key they can’t copy it from someone else like their housemate; they have to get another one from you. You will know if one of your keys has been compromised.
LFIC locks are also a good idea for quick rekeying possibilities. LFIC locks actually have all of the same benefits as SFIC, except they are easier to take apart and determine what the master key is. Anybody with a working key and the knowledge of how LFIC locks work can remove an LFIC cylinder from a commercial lever or knob. It is trivial to take them apart. No special hardware is required. They are easier for the layperson to rekey, but the whole idea of interchangeable core locks is the convenience of not having to take the cylinder apart and change the pins.
LFIC cores can be compatible with other locks in your building that aren’t LFIC so that you can use the same key as other locks but only have one lock with an interchangeable core. This allows you to temporarily change an entry lock to allow contractors to use an entry key only for a weekend, for example.