Key Blanks and Keyways: Profiles, Families, and Blank Numbers

Anatomy of a Key Blank

Schlage's catalog glossary names the main parts of a key:

• Bow: "the portion of the key that serves as the grip or handle."
• Blade: "the part of a key that may contain the cuts and the millings." The millings are the grooves along the blade that give it the profile needed to enter a particular keyway.
• Stop: the feature that sets how far the key goes in. On Schlage B and R family keys, Schlage says "the stop is at the shoulder of the key."

Blanks also come in different lengths to match the number of pins in the cylinder. Schlage lists its Classic keyways as "available in 5- or 6-pin lengths." Kaba Ilco's directory and its 2022 price list both carry separate blanks for Schlage (1145 and 1145A).

How Keyways Work

The keyway's profile only admits blades with matching millings. A blank with the wrong profile will not enter the plug, so the cuts on it are never tested against the tumblers. In a pin tumbler lock, that makes the keyway a first filter, and the bitting the second.

Manufacturers use this in two ways:

• To separate systems. Different keyways let one building, department, or customer have keys that will not enter another's cylinders, even if the cuts happen to match.
• To control duplication. If blanks for a keyway are only sold through authorized channels, fewer people can make copies.

Keyway Families

Manufacturers organize keyways into families. Allegion lists Schlage's conventional and full-size keyway families as Obverse, Reverse, Paracentric (Numbered), Quad, Everest C, Everest D, Everest 29 S, and Everest 29 T. Its small-format and SL families are Everest B and Everest 29 R. Allegion also notes that these families follow different cutting rules. For example, the conventional families have a maximum adjacent cut specification (MACS) and the small-format families do not; see key bitting.

Within a family there can be several keyways. Schlage's catalog says its "Obverse keyway family includes C keyway (standard) and 6 additional options." It also describes its Everest 29 families as "backward compatible" with Schlage's earlier Everest keyways. Families like these allow large master key systems to span many keyways while still being managed as one system.

Blank Numbers: Why a Key Is Called SC1 or KW1

Every lock manufacturer has its own part numbers for its original keys. Aftermarket blank makers publish their own numbering and cross-references. Kaba Ilco uses two schemes side by side. Its 2010 key blank directory and its June 2022 key blank price list both show the same cross-references:

"SC1" and "KW1" are Ilco's EZ catalog numbers for blanks that fit particular Schlage and Kwikset keyways. They are aftermarket part numbers, not the lock makers' own designations. To match a specific keyway, use the lock manufacturer's documentation or the blank maker's current cross-reference.

Open, Restricted, and Patented Keyways

Schlage's key-systems catalog lays out a range of duplication control:

The general pattern is that open keyways use blanks that are widely sold, while restricted keyways limit blank distribution to authorized channels, sometimes requiring written authorization from the end user. Patents on the key or keyway design can support that control for the life of the patent. BHMA's high-security cylinder standard, ANSI/BHMA A156.30 (current edition 2025), lists "key blank control" among its key control attributes. See key control and high-security locks.

Beyond the Flat Blade

Pin tumbler blanks are the most familiar type, but the same idea of a blank shaped to fit a particular lock applies to other key forms. Other key forms have their own pages: dimple keys, tubular keys, and the bit keys of warded locks.

Related Topics

• Key bitting: the cuts made into the blank
• Key cutting and duplication: machines and methods
• Restricted keyways: controlled blank distribution
• Key control: managing who holds and copies keys
• Pin tumbler locks: the lock a flat blank is most often cut for
• Master keying: keyway families and large systems
• Warded locks: the original ward-based key check

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