3M51 - Upright clutch bolt mortice lock



To provide a means of securing sliding wooden doors on offices and rooms where automatic closing action and anti lift protection is required.

Product Codes

Upon request


Mortice lock with formed-up case and welded Forend. Upright construction comprising hook and steady bolts, both of which withdraw completely into the case.

Hook and steady bolt operated by key from either side (full turn to lock or unlock).

Standard Features

  • Brass clutch bolt with anti-padsaw steel rollers.
  • Brass stud bolt to prevent the door being lifted.
  • 5 detainer mechanism with thousands of key combinations.
  • Bolt through fixing facility
  • Steel Body.
  • Built in protection against picking, drilling, force and torque attack.
  • Unique Steel key.


  • Optional micro-switches for alarm systems integration.
  • Can be suited as part of a master keyed system



Materials and Finishes

  • Lock case - carbon steel electro-plated.
  • Clutch bolt and stud bolt - brass.
  • Clutch bolt thrower - high tensile brass.
  • Levers and springs - Brass/phosphor bronze.


Performance/Testing Criteria

  • Mechanical locking mechanism tested to a minimum of 60,000 operations.
  • Saw attack on the clutch bolt 5 minutes.
  • Side Load 13.5KN
  • End Load 1.2KN
  • Tensile Load 5.0KN