Mortise Locks

Why Is a Mortise Lock More Durable Than a Cylindrical Lock? 

A mortise lock installs in a pocket routed into the door edge. The lock case sits inside the door body rather than in a bored hole that concentrates stress at two small points. That means the door sustains less damage around the hardware over years of heavy use. Under ANSI A156.13, Grade 1 mortise locks are tested to 1,000,000 open-close cycles plus a 3,600 lb-force cylinder tension test. That's the standard test minimum. dormakaba's M1000 Series has been independently tested beyond 10 million cycles. For primary building entries, hospital corridor doors, and K-12 main entries, mortise hardware is built to last the life of the building. 

When Cylindrical Is Good Enough vs. When You Need Mortise 

Cylindrical locks are fine for most interior commercial doors, multi-family residential unit entries, and secondary building entries. They're faster to install and lower in initial cost. Mortise is the right call when the opening is a primary building entry, a door in a high-abuse corridor, a healthcare patient room, or any opening where the architect's hardware schedule specifically calls for it. If you're replacing hardware and the existing door has a mortise prep already cut, keep the mortise. Retrofitting a cylindrical into an existing mortise prep wastes the door's preparation and typically looks wrong. 

How Do ANSI Function Codes Work on Mortise Locks? 

The Most Common Functions on Commercial Hardware Schedules 

F01 (passage): free from both sides, no locking. F04 (entrance/office): outside lever controlled by key or button, inside always free. This is the standard for primary building entries that need after-hours lockdown. F05 (classroom): outside always locked, keyed to lock or unlock from outside, inside always free. F07 (storeroom): outside always locked every time, key required, inside always free. F13 (dormitory/exit): inside always free, outside by key, push button can deadlock the latch from outside. Standard for university residence hall entries. 

Specialty Functions Most Distributors Don't Stock 

F17 (hotel/motel): inside always free, outside by card or key, thumb turn deadbolt. F25 (communicating): both sides keyed for communicating rooms between suites or offices. F19 (vestibule): inside free, outside always locked unless held open from inside. The Schlage L Series supports over 40 function options. If your hardware schedule calls for a specialty function, call 877-471-4870 to confirm availability before specifying it on the submittal. 

Which IC Core Prep Works with Which Mortise Lock? 

Mortise locks from Schlage, Sargent, Corbin Russwin, BEST, and dormakaba are available with IC prep. The housing comes with the lock body and accepts interchangeable cores from your existing masterkey program. BEST SFIC prep works with Schlage L Series, Corbin Russwin ML2000, Sargent 7300, BEST 45H, and dormakaba M1000. Schlage SFIC prep works with Schlage L Series only. Arrow SFIC is available on select models. Don't mix formats. BEST SFIC and Schlage SFIC housings share the same external dimensions but use different keyways and core profiles. Cores from one program won't operate in the other's housing. 

Which Mortise Lock Brand Should You Specify? 

For Schlage-Standard Campuses 

Schlage L9000 Series is the first choice for campuses that have standardized on Schlage hardware. It supports 40+ function codes, 33 lever designs, and 12 finishes. It's the most flexible mortise family in the market and the most stocked at distributors nationwide. 

For Healthcare and Northeast US Facilities 

Corbin Russwin ML2000 is the preferred mortise in northeast US hospital and healthcare specifications. It comes in three case sizes (0, 2, and 4 body) to fit different stile dimensions. It's part of ASSA ABLOY and builds to the same institutional standards as Yale (Accentra). 

For BEST SFIC Programs 

BEST 45H Series accepts BEST SFIC cores as standard, not as an upgrade. If the facility is on a BEST IC masterkey program, the 45H is the mortise lock that integrates cleanly without additional IC prep costs.