A lock’s integrity obviously springs from its uniqueness. No two locks are the same. Likewise, the fact that no two keys are the same for distinction is its inherent attribute. Over the centuries, humans have created a wide array of keys, corresponding to the development of more secure lock features or mechanisms.
The basic categorization is: bit, barrel, lever or cylinder. They differ in the bitting, that is the part coming in contact with the locking mechanism. In an ordinary key, the bitting is that ragged edge of the shaft. So in a bit key, bitting cuts are or attached to the shaft just like in a skeleton key. This type evolved into more complicated forms such as the double-sided-bit, multi-bit, and four-bit version called the cruciform. A barrel key is similar to the bit version only that in this sort the shaft takes a tubular or barrel form. This likewise evolved to present day barrels where the shaft’s tip now contains the grooves or bittings. A lever key has cuts indented into the shaft. These cuts correspond to the lock’s loose internal levers, so when it is inserted, the levers properly align releasing the locking mechanism. In a cylinder key, the shaft also bear the bittings, but in distinction, a groove or two runs along the shaft’s length.
Electronics paved computer chips to invade what was once strictly a mechanical territory. Some locks now feature electronic components; consequently, keys embraced present technology. In a transponder key, an electronic transponder is attached to the bow - that part you hold when you use it – transmits a pre-embedded code in the receiver found in the lock. This effectively addresses problems of unauthorized duplications as despite correct shape, a wrong code restricts entry and makes for an additional safety feature. A transponder controls access to the engine. Technology further enabled creation of more distinct versions as in the case of internal cut keys where laser cuts on the shaft’s wide part, sometimes known as blade face. Examples are wavy grooves or sidewinders, and shallow cones of varied depths or dimples. Surely, no amount of force would suffice to open locks with these kinds of keys! Finally, keycards like the ones used to open hotel door locks, are flat cards embedded with chips or magnetic strips which when inserted into a signal-reading device unlocks the door. However you need to be extra careful with such locks because when you lose these keys, only brute force opens the door.
Other categorization depends on the use, say a master key, any kind really, used in conjunction with another one to open a vault or some sealed receptacle. An ignition car key operates the engine but is limited to it.
Locksmith Erith, 020 3868 4490, Fraser Road, Erith, United Kingdom, DA8 1QH, http://www.locksmith-erith.uk/