To provide secure locking of swinging cell doors using third party security management systems (SMS) or conventional key control. The lock can be configured to provide a softer aesthetic apppearance without reducing security.


The 3F51 is a mortice lock of robust construction based on the Chubb Locks Custodial Services large mortice footprint. The main bolt is a sprung latch providing a throw of 25mm, secure locking is achieved by two independent methods:

Electrical Mode: Locking/unlocking by 24 volt DC controlled sequence from an external source (SMS). Bolt withdrawl by handle, which should also be used when closing the door.

Manual Mode: Locking/unlocking achieved using conventional (mechanical) key. Bolt withdrawl by handle, which should also be used when closing the door. Key operates from corridor side only.

Manual Override: In the event of power or communication failure an override key is used to disable electric locking function.

The lock will operate if slammed to shut, however, CLCS recommend that in normal operation the handle is used to withdraw the bolt when closing.


Solid Case Technology - lock case machined from single piece carbon steel.
Steel main bolt, with carbide anti-cutting rollers and 25mm throw.
Unique dual solenoid electric locking latch.
Independent 7-lever locking mechanism.
Factory restricted key section.
Lock provides status monitoring of critical functions and tamper.

Integral baffle arrangements to resist manipulation and interference via the keyhole.


Mechanical locking mechanism tested to a minimum of 100,000 operations.
Handle mechanism tested to a minimum of 300,000 bolt operations.
Solenoid locking unit trested to a minimum of 1,000,000 cycles.
Solenoid  arrangement designed to operate at +/- 10% of 24v DC regulated supply.
Nominal operating current 500mA.

Additional Features

Can be configured to provide cell side furniture to be used where remote release is desirable.
Range of fixings include backplates, stud fixings, locking plate and keeps.
External handle designed to shear under excessive load to prevent damage to internal lock mechanism.
Interchangeable mechanical inner locking unti to enable re-coding.
Gate boxes for steel door application recommended.

This lock is not available under a master key system.

Materials and Finishes

Lock case - carbon steel electro-plated.
Main bolt - carbon steel electro plated.
Main bolt follwer - high tensile brass.
Keys - hardened steel.

Levers and springs - Brass/phosphor bronze.

Total Range

The lock is available in left or right handed variants and can be fitted to steel or wooden doors. For wooden door applications CLCS recommend a minimum door thickness of 54mm.

Fully dimensional customer drawings are available on request to assist with door preparation.