How to change a Mortice Lock

Introduction

Mortice locks are available as either a deadlock or sashlock. A deadlock is operated by a key only; and a sashlock has a deadbolt sprung latch bolt that catches when the door is closed. A handle is required to operate a sashlock. Deadlock Sashlock.

 

Step 1

A mortice lock is secured using two screws one at the top and one at the bottom of the lock. These screws are visible on the locking face of the door. Unscrewing these will allow you to remove the forend plate and lock.

A Deadlock operates the door independently with no handles, examples of sash and deadlock are shown in the pictures above.

A Sashlock means that it operates with a handle, before changing the sashlock the handle will need to be removed in the first instance. You will also need to secure the door in the open position while changing the lock until the handles are replaced.

 

Step 2

It is then important to measure your lock, measure it from front to back it will either be 64mm 2.1/2” (44mm to centre key hole) or 76mm 3” (56mm to centre key hole) typically a lock adjacent to glass panel will be 64mm, but you should check prior to installation. Your new lock should fit the hole the old lock was removed from.  If the lock does not fit into the same hole, you may need to rout the door out to suit the new lock. (Remember to screw the forend plate on at the same time as securing the lock). 

See drawing below – example shows an ERA BS Fortress lock.

Step 3

For the Deadlock version simply follow the above instructions, if you are replacing your existing mortice lock to a ‘British Standard’ version you may need to rout out the box keep on the striker deeper to allow for the 20mm throw on the bolt.

For the Sashlock version you need to make sure the spring loaded latch is at the top and that the angle of the latch suits the closing of the door. Remember to also change your box striker to the one supplied with the lock. To do this simply remove the screws that attach it to the door frame, remove box keep and replace it with the new one. If you are replacing your existing mortice lock to a ‘British Standard’ version you may need to rout out the box keep on the striker deeper to allow for the 20mm throw on the bolt. NB. Please check the fit of your new striker before you attempt to deepen the hole.

Make sure that the curved edge of the striker points the same way as the face of the door when it is open so it closes properly. Once the lock is secured in place you can now refit your handles.

When fitting any product please ensure you use the fitting instructions supplied with every lock