Keyed alike vs. master keyed:
-A master keyed lock can be operated by two or more keys which are NOT cut the same.
-Two or more locks which can be operated by a single key (or multiple identical copies of a key) are said to be keyed alike, not master keyed.
So while it may seem like your house key, which (hopefully) operates every lock in your home is the same as the master key the custodian at the school carries, since his key also operates every lock in the school, it’s quite different.
It’s easiest to explain this if you consider a key to be a password. A lock which is master keyed has more than one password programmed into it, i.e. more than one unique key will operate it. If multiple locks all have the same password programmed into them, but only ONE password, they’re keyed alike.
As locks are simple machines rather than complex computers, the number of available “passwords” is mathematically small. Using a 5 pin key with 6 unique depths (both common values for residential or light commercial locks) yields 6^5 or 7776 possibilities, but that number is cut in half once impossible-to-cut or undesirable combinations are eliminated. A far cry from the typical password requirements even the most unsecure website would require. . . but odds are nobody is planning to cut 3,000 keys and attempt a brute force attack on your home or business.
Regardless, because of the mechanical and mathematical limits imposed, master keying is best done as an engineered system (the alternative being a “shoebox” master key system where random change keys are used in a completely uncontrolled manner, which causes lots of problems).
So when should you consider master-keying? When you need to grant access selectively to one or more locks to certain keyholders, but want the convenience of a single key for yourself or other (hopefully trustworthy) persons.
An example for homeowners might be adding a “yard guy key” to an exterior garage door or storage shed. The key you carry will operate it along with all of the other doors in your home, but your ‘yard guy key’ will only operate the doors you specify.
For businesses/commercial facilities, master key systems are typically much more complex and beyond the scope of what can be described in a little article for our website. Call or email us to discuss a customized solution for your facility.
• The locks on my commercial building are a mess. I’d like to get a master key system in place. How much does this cost?
Before we can answer that question, we’d need to do a site survey. This involves walking the property and tagging each door, assigning it a number, and documenting what hardware is currently installed and evaluating it’s condition. Once that’s done we determine what hardware can stay and what needs to be replaced (to eliminate incompatible keyways, worn-out locks, code violations, etc.) and create a materials list and estimate from that. This can take several hours, depending on the size of the facility.
We do charge a modest fee for the site survey, but we will provide the materials list and door survey with markups to you upon completion regardless of if you accept our estimate. This will be useful (essential, really) for any other bidders from whom you may wish to seek estimates. If you hire us for the job, we credit what you’ve paid for the survey against the final invoice.
We do offer no-charge estimates for this service, but those are limited to providing flat pricing for hourly labor, trip charges, per cylinder charge for master keying, and materials costs for keys, locks, cylinders, etc.