Cylindrical And Mortise Lock Functions

When I first started doing lock work, I was told to be very careful and read the packaging to be certain the lock installed onto the door was the correct finish and operation. My early jobs were restricted to cylindrical and tubular locks. Living in...

A lock is designated as a part number, name and an ANSI “F” (function) standards reference number where applicable. The manufacturer determines the lock part number and name. Most lock names describe their operation. For example, a Sargent Lock 11G30, Communicating Lock has the ANSI function number F80. Not every manufacturer will make all of the ANSI function number locks.

Every ANSI function number has a description, much like the operation. The function numbering began with mortise locks. The ANSI F01 Passage Mortise Lock description for Marks USA is “Latch by knob/lever either side.” The Sargent Lock description for the ANSI F01 Passage or Closet Mortise Lock function description is “Trim from either side retracts latch bolt at all times.” Both say the F01 function mortise locks do not have keyed cylinders or a deadbolt, and the inside or outside knobs or levers will retract the latch at all times.

Because of the number of mortise lock functions, most lock manufacturers list their mortise locks by first dividing them by keyed and non-keyed. The keyed mortise locks are further divided by single and double cylinder and deadbolt or non-deadbolt.

ANSI function numbers were applied starting with F01. The Passage Function is for mortise locks. A passage function mortise lock does not have either a keyed cylinder or a deadbolt.

Different lock types use different ANSI function numbers for the same function. The passage function cylindrical (bored) lock uses ANSI F75. Both bored locks and mortise locks share some of the same functionality, however they are not identical. For this reason, each lock type, mortise, cylindrical and deadbolts have their own unique numbers for each lock function.

A short list of manufacturer’s lock function, the ANSI function numbers and the manufacturer’s descriptions for cylindrical locks:


When ANSI functions are displayed in a catalog, there is normally a drawing and written description of the lock’s operation. The cylindrical lock drawings indicate if there is one or two knobs/levers or a key or push button extending from each knob/lever. The mortise lock drawings indicate if there is one or two knobs/levers or a keyed mortise cylinder, coin turn or thumb turn on the outside or inside.

The length of the description depends upon the complexity of the locks’ operation.

Having the ANSI Function numbers and the description along with the manufacturers’ information can help find the right lock for the application.

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