‘High Security lock’ is a phrase that has been used for centuries to indicate any locking system that provides security over and above the normal locking systems of that period. The current era of what are today called high security locks generally refer only to the lock cylinder. Current high...
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‘High Security lock’ is a phrase that has been used for centuries to indicate any locking system that provides security over and above the normal locking systems of that period. The current era of what are today called high security locks generally refer only to the lock cylinder. Current high security lock cylinders are usually designed to specifically fit in place of the original lock cylinder without requiring any changes to the existing lock chassis. The amount of security provided by the original mechanical connection between the door and frame remains unchanged.
Standard lock cylinders require a single movement in order to set the lock to an unlocked position. The best example is the pin tumbler locking system. As the proper key is inserted into the cylinder, the tumblers are simultaneously moved and aligned at the shearline and the plug can then be turned. A single movement system lends itself most easily to manipulation with lock picks and therefore has a low resistance to lock picking.
High security locks usually require at least two movements in order to set the lock to an unlocked position. One example is the original Medeco lock system. Each Medeco tumbler contains a chisel point and a vertical groove. The key contains angled cuts. A sidebar provides the second locking feature. During key insertion, the key cuts lift the tumblers to the shearline while the chisel points rotate the tumblers as they are fitting into the angled key cuts. If the tumblers are aligned properly at the shearline and the tumbler grooves are rotated to the correct angles, then the sidebar can fit into the tumbler grooves and allow the plug to be turned. Since the tumblers must be both lifted and rotated, there is a greatly increased resistance to picking as compared to a standard cylinder. While all high security lock types have some variation of this ‘two movement’ system, each company has its own patented way to accomplish the same purpose.
Aftermarket key blank manufacturers have been in existence for a century or more. Their key blank catalogs are filled with commercial, utility and automotive key blanks. Lock manufacturers normally welcome aftermarket key blank manufacturers because it makes key blanks for their lock products more easily available for servicing and maintenance in the field.
High security lock manufacturers purposely obtain a patent for their products in order to limit the availability of key duplication in the field. As example, Kaba Peaks keys contain an enlarged section on the top and bottom of the key blank. This extra large section raises an additional pin tumbler to the shearline. The Peaks key blank with the enlarged section is patented and blanks cannot be made by aftermarket key blank companies. Customers purposely purchase patented high security systems in order to be assured that extra keys cannot be easily made except with proper identification and at the locksmith dealer who sold the original system.
Most standard commercial key systems contain five tumblers and ten depth increments. ‘V’ shaped cuts on pin tumbler keys cause a restriction in the maximum deep of cut which can be made next to a very shallow cut. As example, including other factory restrictions, one popular lock company has only approximately 65,000 available key changes for their five pin lock systems. With millions of locks per company made each year, duplicate key changes are a reality in single keyway, stock locks.
High Security lock companies have developed ways to increase the available key changes well above the restrictions on standard key systems. One idea is the use of multiple keyways which are regionalized across the country. Another idea is to add more tumblers. Companies can also use their ‘second movement’ feature to increase possible combinations. There are hundreds of Medeco angle-cut combinations which can be used to multiple the amount of times each standard key cut combination can be used which then produces millions of individual key cut combinations without interchange.