predominately common key sections that are as easily identifiable as the key sections made by companies that produce only one key section. Of all the domestic keys in use today, the Arrow, Kwikset, Schlage C, Weiser Lock, and standard Yale key sections are some of the most common and distinctive. All skilled locksmiths, and even trainees with minimal experience, should be able to differentiate and identify these common key sections immediately. Throats and Shoulders The throat of a key is an extension that con- nects the working part of the blade to the bow. On most keys, the throat is usually wider than the working part of the blade. The width and length of a throat are determined by the physical configuration of the cylinder that a specific key operates. Throats can be short, medium, or long, depending on the distance between the cylinder face and the tumblers. The majority of residential and commercial keys have short throats. Many automotive keys have long throats due to the extended distance between the tumblers and the cylinder face. The throats of some keys are sharply defined, while others are barely noticeable, and some keys have no obvious demarcation between the working part of the blade and the bow. In the latter case, there’s simply a short, medium or long uncut extension of the blade. The side mill- ings may terminate in this extension, or they may extend into the bow. The shoulder of a key is a noticeable step between the throat and the working part of a blade. Most shoulders are perpendicular to the blade and are sharply defined. However, some shoulders have rounded or indistinct corners, and a few are angled at less than 90 degrees. Most single-sided keys have only one shoulder, and it’s usually located on the top of the blade. Most double-sided keys and some single-sided keys have shoul- ders on both the top and bottom in a dual configuration. Dual shoulders are usually 28 KEYNOTES JANUARY 2015 “Each unique key section enables a specific blade to fit into an equally unique, mirror-image keyway in a specific cylinder plug.” located at the same horizontal position on most keys. Certain other keys, like Titan, have top and bottom shoulders located at different horizontal positions. Like throat width and length, the location of a shoulder is determined by the physical configuration of the lock that a specific key operates. When you insert a key into a key- way, the shoulder stops the key against the front surface of the cylinder face or against a specific surface within the cylinder plug keyway. This aligns the pin seats with the tumblers to establish a clear shear line be- tween the cylinder plug and the cylinder housing. If a key has a very indistinct shoul- der or no shoulder at all, the end of the blade or a small step in the end of a blade acts as a stop. A few oddball keys actually use the perpendicular edge of the bow to act as a stop against a cylinder face. Runouts and Their Significance Each different milling shape produces a unique feature called a runout. Runouts are located where the millings terminate, usu- ally in the shoulder, but in some cases they extend into the bow. Milling shapes can be triangular, square, round, elliptical, angled, irregular, part round and part flat, or in any combination of these physical characteristics. Every different milling shape, or combina- tion of milling shapes, results in a uniquely shaped runout. A square milling appears as a square-ended runout, and a round milling appears as a round-ended one, etc. Some runouts appear to be pointing leſt, right or center as determined by the differ- ent shapes of the millings. These features are very useful when making difficult key iden- tifications and when comparing keys and blanks. If the runouts don’t match perfectly when keys and blanks are placed side-by- side, you’re probably making a comparison with the wrong key blank. Multiple Key Selections and Key Selection Identifiers The Best Lock, Chicago, Corbin/Russwin, Master Lock, Sargent, Schlage and Yale companies each produce many different key sections in their individual product lines. Some of these individual lock manufactur- ers’ key sections are difficult to compare with other key sections in their own prod- uct lines. Fortunately, some of these OEM lock companies stamp key section identifiers on most of their original keys and blanks. Key section identifiers are usually stamped on the throat and near the shoulder on keys that have this feature. Depending on the manufacturer, these identifiers can be a single alphabetic letter or a combination of alphabetic and/or numeric markings. Key section identifiers are very helpful in the identification and comparison of keys and blanks. It’s not usually necessary to examine the blades of keys that have key section identifiers unless you’re comparing one with a key or blank that does not have identifying markings. Unfortunately, the use of key section identifiers is somewhat inconsistent even within some companies that use them. The Master Padlock and Yale lock companies stamp key section identi- fiers on some of their keys and blanks but not on others. The majority of Best, Sar- gent, and Schlage original keys and blanks have key section identifiers stamped on or WWW.ALOA.ORG
