Even in the technical era of smarthomes and automated alarm systems, the first and most important elements of home security are basic locks. In most Canadian homes, that’s a cylinder lock.
The main advantage is that most lock manufacturers design hardware so that the cylinder can be changed without removing the surrounding lock. This allows a locksmith to replace or modify the cylinder.
There are various types of cylinder depending on region, door thickness, and how locks are used. Most lock cylinders are also known as profile cylinders, and use a pin tumbler system.
This design has an outer casing with a cylindrical opening in which a plug fits. The plug has a slot known as the keyway allowing the key to be inserted at the open (keyhole) end, and a cam or lever at the other end which retracts the locking bolt when the plug is turned. Variable-length pins are fitted into the plug so that only a key with the correct dimensions will position the pins so the plug can be rotated. Above each key pin is a spring-loaded driver pin. The outer casing has a series of holes to accommodate the driver pins.
In an individually-keyed system, only one key will work in a particular lock. In a keyed-alike system, the locksmith outfits the cylinders in more than one lock (such as front and back doors) to use the same key.
A master key allows one key to open multiple locks along with the individual lock key, such as landlord might use to access rental units. This involves installing extra spacer pins in each lock so the master key will work in all of them. This allows the cylinder to have two shear points where the cylinder will turn – one for the drivers and pins, and another for the spacers and drivers.
In complex cases, there might be a grand master key and subordinate masters. For instance housekeepers in a large hotel might have a master key for their own section, but the hotel manager would keep a grand master key.
A pin tumbler lock may be vulnerable to lock picking methods and tools. To protect them, more secure cylinder locks also include additional security pins that are more resistant to these attacks.
Newer alternatives might have a cylinder which rotates by electric current rather than manually. These may be stand-alone locks requiring a special magnetic key, connected to a device such as a keypad or biometric scanner, or connected to a whole-home security system.
Even these updated versions can be rekeyed by a qualified locksmith to meet Canadian homeowner needs – or rescue from an accidental lock-out!