Wafer Locks: Flat One-Piece Tumblers from Felter to the Automobile

How a Wafer Lock Works

Wikipedia describes the mechanism this way. The wafers sit in slots cut through the plug, and springs push them outward into grooves in the outer casing. While any wafer sticks out into a groove, the plug cannot turn.

Each wafer has a rectangular hole in its middle, and the position of that hole varies from wafer to wafer. The key slides through the holes. Its cuts must move each wafer just far enough that both edges sit flush with the plug. A wafer moved too little, or too far, still blocks the plug.

Lockwiki lists the parts as wafers, springs, the plug, the outer cylinder and a cam on the back of the plug that works the bolt. Wafers provide differs, the variations between keys, through "a different size or a different protrusion in the center." Lockwiki adds that master keying is possible with wafers that have stepped or divided bitting areas. See master keying.

Arrangements

According to Wikipedia, the most common arrangement is "the single-bitted, five-wafer configuration," found on desk drawers, cabinets, key switches, lockers, cash boxes and electrical panels. Wafer locks can also use double-bitted keys. In automotive locks the wafers are often set in opposed pairs, so the key is cut on both edges. Lockwiki notes that more advanced wafer locks can block the plug at the top and bottom and alternate wafers between the two.

Some wafer locks add a sidebar, a separate bar that must also be released before the plug turns.

Names: Wafer, Disc, Plate

The names in this area overlap.

• Lockwiki lists "wafer tumbler, disc tumbler, plate tumbler" as other names for the wafer.
• Collector Michael Newman notes that wafer locks "have also been referred to as disk locks and plate tumbler locks."
• Wikipedia warns that the wafer lock "is often incorrectly referred to as a disc tumbler lock, which uses an entirely different mechanism."

That other mechanism is the rotating-disc disc detainer. Hardware catalogs still use "disc tumbler" for wafer-type cabinet locks; see cam locks.

History: Felter and Shepardson

Philo Felter of Cazenovia, New York, patented a wafer lock in 1868. Wikipedia calls it "the earliest record of the wafer tumbler lock in the United States." His lock used a flat, double-bitted key. Google Patents lists U.S. Patent 76,066 with a date of March 31, 1868. Wikipedia notes this was three years after Linus Yale Jr.'s pin tumbler mortise lock patent. See Linus Yale.

Two years later, Hiram S. Shepardson produced a wafer lock that used a single-bitted flat steel key. Newman, writing in a four-part history for collectors, says lock historians credit "Felter for the double-sided variety and Shepardson for the single-sided."

Then development stalled. Newman reports that in August 1878 the Yale Lock Manufacturing Company bought Shepardson's company, the United States Lock Company, along with its patent. Two months later Yale bought Felter's American Lock Manufacturing Company. "Over the next thirty-five years," Newman writes, "only about two dozen patents were issued for locks of the wafer design." He asks whether the purchases were made to protect Yale's young pin tumbler cylinder from competition. That is his question, not a conclusion (see Yale and Towne).

History: King Lock and the Automobile

Wafer locks found their market in cars. Newman's account:

• In October 1913, Emil Christoph filed a patent for a new wafer lock with a double-bitted key. It was assigned to the King Lock Company of Chicago.
• Briggs & Stratton started using King wafer locks in its ignition switches. Clum Manufacturing introduced its own wafer-lock ignition switch in 1916, and the switch maker Caskey Dupree was also supplied with King locks.
• In 1924, Briggs & Stratton's Edward N. Jacobi filed a patent for a five-wafer lock with a single-sided key.
• A later Briggs & Stratton patent standardized pre-cut wafers to match key cuts of set depths, "just as had been done with the pin-tumbler lock many years earlier."
• The 1924 Hupp 8 was the first car to use the new single-bitted lock. In 1925 it went on Ford sedan doors and other cars.
• By 1929, Newman writes, Briggs & Stratton "was the largest producer of automobile locks in the world, supplying by some accounts, between 75 and 90 percent." He adds: "After 60 years, the wafer lock had finally found a home, as an automobile lock."

Wafers were not the only option. In an article on vintage auto locks, Locksmith Ledger notes that pin tumbler lock systems from makers such as Yale, Sargent and Corbin were popular during the 1920s. It also reports that GM introduced a sidebar system on its 1936 models. Lockwiki credits Chicago Lock and Briggs & Stratton with sidebar wafer locks in the 1930s; see sidebar locks.

Wikipedia adds a British thread: Josiah Parkes & Sons of Willenhall introduced the wafer lock in the UK in 1929, supplying the Wilmot Breeden company. That passage relies on Wikipedia alone and is flagged.

Lockwiki describes wafer locks today as "the most common form of automobile lock," with many newer models adding electronics. That present-tense claim is attributed, not stated as fact.

Security Level

Lockwiki classifies wafer locks as "low to medium security," and notes that low-security cabinet, desk and drawer locks are commonly wafer designs. Ratings belong to individual products. For tested high-security cylinders, see UL 437, EN 1303 and high-security locks. This article does not describe ways of opening wafer locks without a key.

Related Topics

• Pin tumbler locks
• Disc detainer locks
• Sidebar locks
• Cam locks
• Linus Yale
• Yale and Towne
• Master keying
• UL 437
• High-security locks

Sources