Retrofit Hardware Opportunities: Upgrading Mechanical Locks

Oct. 2, 2014
A replacement lock solution can be as simple as a retrofit installation of the same manufacturer's leverset where a knobset once was, or as complex as implementing a networked access control system throughout a facility.

The passage of time, use and abuse, life/safety concerns, new technology and designs and new code requirements result in the need to upgrade lock hardware in commercial and institutional applications. Choosing a replacement lock can be as simple as installing the same lock manufacturer's leverset where a knobset was previously, or as complex as implementing an electromechanical access control system throughout an entire facility.

More than 60 lock functions are available for cylindrical and mortise locksets. These available functions vary from lock manufacturer to manufacturer.  New lock functions for cylindrical (bored) and mortise locks enable door operation to meet specialized needs.

Most functions use the American National Standards Institute (ANSI) Standards. Having set standards enable locksmiths to compare different manufacturers’ products. But while bored and mortise locks offer some of the same functions (i.e. Office, Storeroom, Entrance), there sometimes are differences in their operation.

Lock manufacturers have introduced lock functions to their product lines to accommodate specialized needs. Some examples of these include vandal resistance and school security applications.  Vandal resistant cylindrical and mortise locks are designed to resist abusive acts without unlocking or being damaged. An example is the introduction of the "clutch" mechanism.

School security locks are equipped with indicators that visually verify whether the classroom door lock is locked or unlocked. A number of commercial/institutional lock manufacturers offer school security type locks. Two examples are the Marks USA LocDown Classroom Intruder Mortise Lock and the PDQ 135 Cylindrical Locks. The Marks USA LocDown has a large indicator above the lever on the interior trim that is green when unlocked and red when locked. A mortise cylinder in the interior trim can be used to lock the exterior lever. The PDQ 135 Classroom Intruder Cylindrical Lock has an LED on the interior rose above a spring loaded button. Pressing the button will illuminate red when the exterior lever is locked. A keyed lock cylinder in the interior lever can be used to lock the exterior lever.

Note: Some of these lock functions have not been standardized, although the locks meet or exceed at least one of the ANSI/BHMA bored or mortise lock construction and operational grades.

Cylindrical Lock Replacement

When replacing a cylindrical or mortise lock with a different type or brand of lock, there are several things to consider.

  1. Door prep through bolt locations for cylindrical leversets. The most common through bolt location is 12 and 6 o'clock, having a 5/16" to 3/8" diameter cross bore for the stud and bolt (screw). Some lock manufacturers use different locations. For compatibility, some brands of lever locks come with the ability to change the through bolt location to match an existing door prep.
  2. Lock cylinder dimensions in the exterior lever. It is not uncommon for facilities to use a keyway that is not the locks’ default choice. Sometimes the diameter of an existing lock cylinder, which is part of the company's masterkey system, is either smaller or too large for the new lock's lever. A number of lock manufacturers offer competitive keyway replacement lock cylinders in the more popular keyways. Some lock manufacturers offer different exterior levers for their cylindrical locks that accept interchangeable and removable cores and specific competitors’ original equipment lock cylinders.
  3. Diameter of the rose. Schlage ND Series leversets have a 3-7/16" diameter rose;  PDQ Series leversets have a 3-3/8" diameter rose and Marks USA Survivor Series Grade 1 leversets have a 3-7/16" diameter rose. If the upgrade lock rose is smaller diameter, a paint or finish ring can be exposed. This is not a problem for upgrading from a knob lock to a lever cylindrical lock, as the average knob lock rose is significantly smaller in diameter.

Cylindrical locks have been upgraded to include a clutch mechanism that disengages the exterior lever from the latch retraction mechanism when locked. Should the exterior lever be force rotated in the locked condition, the lever will either stop against a stop or disengage when force rotated. Depending upon the lock manufacturer, the term Vandal Resistant can be used on this type of lock or locks that have additional mechanisms to resist unauthorized access.

Special application cylindrical locks include ligature resistant and locks equipped with hospital push-pull handles.

Mechanical Pushbutton Locks

Mechanical pushbutton locks offer an alternative to carrying a key. These pushbutton locks are easy to program. Most do not have to be removed from the door in order to change the code. They use a single access code, usually three to 10 digits in length (so users have the option of memorizing an area code and telephone number as the code). Locks can be ANSI/BHMA Grade 1 or 2 certified. Mechanical pushbutton locks are available for different applications including trim for an exit device. Most commercial pushbutton locks are equipped with a key override lock cylinder. A partial list of mechanical pushbutton lock manufacturers includes Alarm Lock, Codelocks, Kaba Ilco (Simplex) and Lockey USA.

The electrical upgrade for cylindrical locks includes either a solenoid or motor to lock or unlock the latching mechanism to be part of an electronic access control system. Some electrified cylindrical locks are available with a request-to-exit (REX) output.

Mortise Lock Considerations

Installing a different lock manufacturer’s mortise lock has its own set of considerations. These include the size of the mortise body (height and depth), the location of the latch bolt and deadbolt (if equipped), the locations of the hub and the mortise cylinder/thumbturn opening. With any differences in the new mortise body, the existing trim may not be compatible. Sometimes rose trim can be relocated and still provide sufficient coverage without having to replace the trim.

As with cylindrical locks, mortise locks are available with ligature resistant and hospital push-pull paddle handles.

TownSteel Rejuvenator Kits enabled specific lock manufacturers’ knob operated mortise locks to be upgraded to lever equipped mortise locks. The kits contain levers, through bolt mounted escutcheon or rose trim, and spring cages.

Upgrades are available for a number of manufacturers’ mortise locks to electrified, enabling keyless access and egress control. Locks can be purchased new with electrification or modification kits can be used to upgrade a customer's mortise locks. Electrified mortise locks are available from Best, Command Access Technology, Corbin Russwin, Marray, PDQ, Sargent Lock, Schlage and SDC (Security Door Controls) to name a few manufacturers. Companies that will upgrade a customer's mortise lock include ACSI and Command Access Technology. In addition, companies that sell upgrade kits in order to field electrify a customer's lock include Architectural Control Systems Inc. (ACSI), Command Access Technology and SDC.

Electrified mortise locks can be available with different options including request-to-exit (REX), door status, and latched and locked status outputs.

Exit Devices

Exit devices are available with crossbar or push rail mechanisms that unlock and retract the latch(s) in order to open an outswinging door. They come in vertical rod, mortise and rim configurations. A consideration for exit devices is the clunk sound that occurs when the device's latch bolt extends, securing the door. Attempts have been made by exit device manufacturers to decrease the sound level.

For school security, exit device manufacturers offer double cylinder options to lock the exterior trim from the interior. In addition, Von Duprin has introduced the Classroom Security Indicators for the 98/99 Series exit devices. A lock cylinder or T-Turn equipped center case locks or unlocks the exterior trim. Labels indicate the direction of turn to lock or unlock.

Von Duprin also offers the Concealed Vertical Cable (CVC) System Exit Device. The CVC replaces the vertical rods on specific models of the 98/99 and 33/35A series exit devices. The major advantage is the ability to adjust the latch height for both the top and bottom using one adjustment point without having to lower the door.

Electronics have been added to exit devices in several ways. The first is the development of the alarmed exit device. The alarmed exit device will when egress is attempted, sound an alarm notifying that an unauthorized individual has opened the door. Alarmed exit devices are installed onto non-entry doors, including movie theatre doors, market and back doors.

Detex, Precision Hardware (S&G) and Securitech manufacture heavy duty, multi-point alarmed security exit lock devices that provide a higher level of security against hammering, prying, wedging and employees. These devices are designed for limited use doors to prevent unauthorized egress as well as access. The Precision Hardware Arm-A-Dor device and the Securitech Trident device are for exit-only doors and are designed without key access from the outside. The Detex Exit Control Lock Series is available as a single point (flat plate deadbolt), two-point (surface vertical rod assembly) and three-point (deadbolt and vertical rod assembly).

For electronic access control for exit devices, the first upgrade was to electrified trim. The trim could be electrified to unlock when powered (Fail Secure) or when power is removed (Fail Safe). Trim electrification can be used for limiting access as well as creating passage mode where exit devices are required. This method was used for a number of years until Electric Latch Pullback was developed moving the electronics into the exit device rail, mimicking the movement of the push pad. Although trim electrification is still being installed, most existing application upgrades are using Electric Latch Pullback.

Electric Latch Pullback can be installed into the extruded rail assembly of specific makes and models of push pad equipped rim and vertical rod exit devices. An important application keeps a Fail Secure exit device continuously energized, electronically dogging the device creating passage mode (push/pull condition). Electronic dogging eliminates the need to depress the push pad to egress or a credential for access.

The following is a partial list of companies that offer electric latch pullback equipped exit devices. They include Cal-Royal, Command Access Technology, Hager Companies, Sargent, SDC (Security Door Controls) and Von Duprin. There are a number of companies that offer Electric Latch Pullback kits. In addition, there are companies that will electrify your customers’ exit devices.

Standalone Electromechanical Locks

The next level of electronic access control upgrade for commercial and institutional cylindrical, mortise and exit devices is the standalone electromechanical lock. These all-in-one credential and locking mechanism devices are available hardwired and battery powered. A partial list of manufacturers and products include Alarm Lock Trilogy, Codelocks CL Series, Kaba E-Plex, Linear (IEI) LS Series, Marks USA iQwik, Sargent Profile Series, Schlage CO Series, SDC EntryCheck and Stanley EL Series.

These standalone locks provide an alternative to key operated locks. Depending upon the manufacturer and model, credentials options include keypad with a high number of user codes, Proximity Card or Smart Card.

A significant advantage of these locks is keying. Because each lock is programmed individually, keying charts that could not be combinated on a pin tumbler masterkey system can easily be programmed onto whichever locks each credential is authorized for access. Programming a standalone electromechanical lock is accomplished at each lock using the keypad or a laptop with the computer program or transfer mechanism.

Depending upon the manufacturer and model, some PC programmable standalone electromechanical locks have one or more of the following features: audit trail, day/date calendar, holidays, automated lock/unlock schedules, user hierarchy, single access and dual credentials.

Standalone electromechanical locks are available in different styles that can fit just about any applications. Most commercial application standalone electromechanical locks are equipped with a key override lock cylinder.

Schlage’s C0-200  standalone offline locks use the Schlage Express software and optimize the available office and privacy functions. Pressing the privacy function button locks the door and locks out the reader. When the occupant leaves the room, the CO-200 lock reverts to unlocked.

Some standalone electromechanical locks are designed with upgradable  credentials. For example, a facility started with keypad only standalone electromechanical locks. Over time, a decision was made to change to Proximity Cards. The standalone electromechanical lock manufacturers credential was changed from keypad only to keypad and proximity or proximity only without having to purchase new locks.

Networked Locks

The latest upgrade for commercial and institutional cylindrical, mortise and exit devices are the networked electromechanical locks, which eliminate the need to go lock-to-lock to keep each lock up to date doing audit trail downloads and programming uploads.

Networked electromechanical locks are part of a wireless or hardwired Local Area Network (LAN). A PC is used to program the functions of each lock. Networked locks can upload information from the computer and download audit trails, battery condition, etc. The information uploaded can include adding and deleting users, time schedule changes, user group information, etc.

Additional advantages of networked electromechanical locks are emergency lockdowns and easily deleting a user without having to go to each lock to remove their access rights. Some wireless networked locks notify when batteries need replacing.

Some electromechanical networked lock manufacturers offer an upgrade path using retrofit kits to convert a standalone lock to a networked lock without having to purchase a new complete lock.

Connecting each of the locks with a PC requires using the lock manufacturers ‘operating software or a third party operating software. For example, Alarm Lock offers free software for the entire Trilogy family of products. Other manufacturers require third party software to operate their locks.

Not all third party software is the same. Before considering purchasing operating software, determine exactly the functionality wanted from the networked electromechanical locks. For example, some third party software has a remote lockdown capability and the optional inside pushbutton functionality can be optimized. Some software does not offer this functionality.

Keri System provides integrated access control system software for different networked electromechanical locks. They offer software with or without hardwired functionality. Doors.NET is their latest access control software application. Note: Keri System has a You Tube Channel where topic specific training videos may be viewed.

For More Information

The following is a list of manufacturers discussed in this article and their web sites.

Architectural Control Systems Inc. (ACSI):

Alarm Lock:

Stanley/Best Lock Corporation:


Codelocks Inc.:

Command Access Technology:

Corbin Russwin:


Hager Companies:

Kaba-Ilco Corp.:

Keri Systems:


Marks USA:



Precision Hardware (S&G):

Sargent Lock:





Von Duprin: