Early Development and Design of Wafer Tumbler Locks
– Philo Felter patented the wafer tumbler lock in the United States in 1868.
– Hiram S. Shepardson developed a different type of wafer tumbler lock with a single-bitted flat steel key.
– Yale Lock purchased Shepardson’s company, The United States Lock Company, and Felter’s American Lock Manufacturing Company in 1878.
– A cylindrical wafer tumbler lock consists of flat wafers and a cylindrical plug.
– The wafers are fitted into vertical slots in the plug and are spring-loaded.
– The wafers protrude into wide grooves in the outer casing of the lock, blocking rotation of the plug.
– The key must have notches corresponding to the height of the hole in each wafer to align the wafer edges with the plug.
– Improperly bitted keys or the absence of a key will prevent rotation of the plug.
Types and Wafer Arrangements
– The most common wafer tumbler lock configuration is the single-bitted, five-wafer arrangement.
– This configuration is found in desk drawers, cabinets, key switches, lockers, cash boxes, and electrical panels.
– Some wafer tumbler locks use a stack of closely spaced wafers designed to fit a specific contour of a double-sided key.
– Wafer tumbler locks can use single-bitted or double-bitted keys.
– The operating principle remains the same regardless of the wafer arrangement within the plug.
Crushable Wafer Tumbler Locks
– Some manufacturers developed crushable wafer tumbler locks to simplify rekeying.
– Locksmiths could replace all the wafers with identical crushable wafers and crush them to fit the key.
– This method had reliability issues, such as debris remaining in the plug and uneven crushing of wafers.
– Debris could cause wear and occasional jamming of wafers or the plug.
– The system of crushable wafer tumbler locks was eventually abandoned.
Vulnerabilities of Wafer Tumbler Locks
– Most wafer tumbler locks with poor tolerances can be opened using a set of jigglers or try-out keys.
– Jigglers are designed with common key patterns and are used to rake the lock until it opens.
– Wafer tumbler locks with poor tolerances are susceptible to this method of forced entry.
– The use of jigglers bypasses the need for a properly bitted key.
– Locks with higher tolerances are more secure against this type of attack.
Advantages, Applications, and Future of Wafer Tumbler Locks
– Easy to manufacture and install
– Cost-effective compared to other lock types
– Smooth operation with minimal friction
– Can be rekeyed without replacing the entire lock
– Suitable for both indoor and outdoor use
– Common applications include residential doors, office cabinets, padlocks, automobile doors, mailboxes, and lockers
– Vulnerabilities include susceptibility to picking and impressioning attacks, limited key combinations, and potential wear over time
– Continuous improvements in design and materials
– Integration with electronic access control systems
– Increased focus on keyless entry solutions
– Development of advanced anti-picking mechanisms
– Growing demand for smart lock features in wafer tumbler locksSources: https://en.wikipedia.org/wiki/Wafer_tumbler_lock
