Changeable Function Mortise Locks

Jan. 11, 2011

The mortise lock has been around for more than 100 years, installed into commercial buildings and residences. The mortise lock is stronger and has more function choices than cylindrical or tubular locks. The reason is the case is larger and more parts can be installed.

Mortise locks can have a very long serviceable life. I have serviced many mortise locks that have been in operation for a long time, some for more than 80 years. However, at some point mortise locks do wear out and need to be replaced.

Today, there are more than 50 different mortise lock functions. Some of the more common functions are the Office/Entry, Storeroom, passage, and Classroom. There are mortise lock functions for lock bodies having a single lock cylinder with or without deadbolt, double lock cylinders with or without deadbolt, deadbolt only and non-keyed.

Most mortise locks are sold for one or two specific functions. To make life easier for locksmiths, several mortise lock manufacturers have developed what I call “convertible mortise locks” which can be converted to operate a number of functions either without additional parts or with a just a few additional parts. The lock manufacturers include the Sargent Multi-Functional Lockbody and the Schlage L9050 Universal Case. Both of these convertible mortise locks are not equipped with a deadbolt.

Sargent 7800 and 8200 mortise locks are certified to meet ANSI A156.13, Series 1000, Operational Grade 1 and Security Grade 1 standards with all standard trims. The 7800 and the 8200 Series mortise locks were introduced in the early 1990s. The 7700 and the 8100 Series Sargent mortise locks were introduced during the 1970s. In the early 1990s, 8100 Series mortise locks were modified to accommodating through-bolts. The 7700 and 7800 Series mortise locks are designed for knobs. The 8100 and 8200 Series mortise locks are designed for levers and are equipped with spring cages. The 7800 and 8200 Series mortise locks use basically the same door prep as the 7700 and 8100 Series.

Chart 1 lists the functions that the Sargent Multi-Functional Lockbody can provide.

The Sargent Multi-Functional Lockbody is available as an 8200, R8200 and 7800 mortise locks. To change the function of the lock bodies, Sargent has a green catch screw and a red locking piece. The green catch screw can be threaded into three different numbered locations on the body. One is for 05, 37 and 38 functions, the second is for 04, 06, 13, 17 and 31 functions, and the third is for the 36 function. The red locking piece can be turned to face the rear or front of the lock body.

For example, ANSI function F07 Storeroom requires the green screw to be placed in the number two position once the hub has been rotated 45 degrees. Rotating the hub 45 degrees and inserting the green screw makes the outside lever/knob rigid. Three threaded holes each have the function numbers.

To create the Asylum function, ANSI F30, the red locking piece must face the backside of the lock body. Positioning the red locking piece facing the back of the lock body makes both hubs rigid, not permitting the outside or inside levers or knobs to rotate.

Schlage L9000 Series mortise locks are certified to at minimum meet ANSI A156.13, Series 1000, Grade 1 Operational and Security with all standard trims.

The Schlage L9050 Universal Case is a non-deadbolt equipped mortise lock body. The Schlage “L” mortise lock was introduced in about 1985, replacing the “K” lock. The “K” Series Schlage mortise lock was introduced in the 1960s and was sold through the early to mid-1980s. Although the door prep is different (thru-bolt positions) for the “K” and the “L” mortise lock cases, a standard escutcheon or sectional trim will cover just about any modification.

The Schlage L9050 Universal Case can be transformed into nine different functions, as shown in Chart 2.

Changing the function on the Schlage L9050 Universal Case requires using specific cams on the inside and/or outside lock cylinders and installing the chassis in either the locked or unlocked position. For this article, the Schlage L-Series Cam (AKA Clover Cam) permits the mortise cylinder plug to be rotated 360 degrees.

The Schlage L9060 (AKA Straight Cam) cannot be completely rotated. This limits the functionality to retracting a latch, not extending or retracting a deadbolt or unlocking the mechanism. For example, the L9060 cam is used on the exterior of the L9060 function mortise lock to retract the latch. The L-Series Cam is used on the interior to unlock or lock the mortise lock.

Mortise cylinder cam part numbers vary depending upon the style of lock cylinder (i.e. Classic, Everest or SFIC). Classic mortise lock cylinders have two holes for screws. The Everest (and Primus) has one offset screw hole. The IC (including SFIC) has a center hole.

The ANSI function F09, L9060 Apartment Entrance function mortise lock, has a mortise cylinder and a knob or lever on the outside and the inside of the door. The inside lock cylinder does not retract the latchbolt. The inside lock cylinder locks or unlocks the outside lever. The outside lock cylinder only retracts the latchbolt; it cannot lock or unlock the outside lever. The outside lock cylinder is keyed different than the inside lock cylinder. This way, renters can gain access into the building but cannot unlock or lock the outside lever.

The Apartment Entrance latchbolt is operated by lever on either side, except when made inoperative by the key operating the inside lock cylinder. When outside is locked, the latchbolt is retracted by key from outside or by operating inside lever. The Schlage Apartment Entrance mortise lock has an auxiliary deadlatch. The Apartment Entrance mortise lock is also known as a vestibule lock.

Both the Sargent Multi-Functional Lockbody and the Schlage L9050 Universal Case can be order without trim or a front. This way, these locks can be used to replace existing locks without having to order a specific lock function.

For more information, contact your local locksmith distributor or the following companies mentioned in this article.

SARGENT Manufacturing Company, 100 Sargent Drive, New Haven, CT 06536-0915. Telephone: 800-727-5477. Web Site:

Schlage Lock, 3899 Hancock Expressway, Colorado Springs, CO 80911. Telephone: 877-671-7011. Web Site: