Changing a mortice sashlock latch
Mortice sashlocks are termed as for either left or right opening doors, this depends upon the way the curved side of the latch in the lock meets the striker plate on the door jamb as the door is closed. Most sashlocks can easily be adapted to suit either left and right handed doors by reversing the latch in a mortice lock.
The following describes how to reverse the latch.
- Release the screw holding the side plate on to the side of the lock and lift off the side plate.
- The latch should be visible and is usually held in place by a spring on a locator pushing the latch out.
If the door handle cam is positioned above the latch, just lift the cam off and put it to one side - the cam will go back into the lock before the reversed latch is fitted (the cam is shown under the latch).
Using a small screwdriver, push the locator against the spring towards the latch to unseat the locator. NOTE: take care when compressing the spring as the locator and spring tend to fly off.
Remove the locator and spring.
Remove the latch from the lock and turn the latch over so that the curved side of the latch is reversed (i.e. if the curved side was uppermost before, turn it over so that the curved face is downwards or visa versa). The two orientations of the latch are shown to the right.
If the door handle cam was under the latch (as shown above), lift it off and put it to one side - on re-assembly, it will go back after the latch has been fitted.
If the door handle cam was originally positioned above the latch (the opposite to that illustrated), start by relocating the cam in the hole in the backplate of the lock - make sure that it is orientated to accept the latch.
Position the spring and locator in the back of the latch and fit the latch into the body of the lock in the required orientation.
Using fingers, small pliers or similar, push the locator against the spring so that the locator can be fitted.
If the door handle cam was positioned below the latch, it needs to be assembled now above the latch (as shown to the right). Relocate the cam in the hole in the backplate of the lock - making sure that it is orientated to operate the latch.
Before replacing the side plate, it wouldn't hurt to apply a spot of grease to the lock and latch mechanism.
Replace the side plate making sure that the upper end of the door handle cam fits into the hole in the side plate. Replace the screw to secure the side plate - the side plate should not be pulled down by tightening the screw, this would indicate something inside the lock is miss-aligned.
Before fitting the reassembled mortice lock into a door, check that the handle cam moves freely and that the latch moves smoothly.