Graphical Construction Glossary >> Doors. >> Door Hardware >> Night Latch

Night Latch
An extra lock on a door in addition to the main lock. It is fixed to the face of the door and it has a spring loaded latch bolt. AKA Nightlatch
A small button control on a nightlatch that can hold the latchbolt open or override the spring loading and turn the latch action off making the latchbolt in effect a deadbolt.

A commercial night latch
Nightlatch : A commercial latch
Image provided by Hafele Australia Pty. Ltd.

Nightlatches are a type of small and specialised rim lock that are used in their millions around the world where cast effective and basic security is need. They are not intended to be the ultimate and uncrackable lock.
They fix to the face of the door and the strike or receiver fits to the face of the door jamb. Unlike the older type of rim locks that can be fitted with different types of furniture with these latches what you see in the packet is what you get. There is no need for handle options as these latches are extra additions to the main door lock and furniture.

They are designed for their intended use which is to be locked when the building empty and then opened and left open while the building is occupied during the day and then in residential situations they are locked at night , thus getting the name night latch.

All these latches can be used on left or right hand doors by simply turning them the other way. Just be aware that the cylinder hole is not exactly in the centre so if you want to keep all the locks exactly the same height then the holes will have to be slightly different, left to right.

Again the lock can be opened and the bolt reversed to suit opening out doors or opening in doors. the one above had the latchbolt set for a door that open outwards. The lock below is set for a door that is opening inwards.

A nightlatch with a snib
Night Latch : A household range night latch with a snub
Image provided by Hayfield Australia Sty. Ltd.

Here is a budget style lock that has a feature which I like. The fact that the strike plate has a return into the jamb so that extra screw fixing can be used. Obviously it is a little harder to fix but I think the extra fixing is worth it. This type of lock has a snub. The small button to the right of the knob. This is used at night-time to lock the latch firmly. (Think about not being able to open it with a credit card).

A schematic section through a nightlatch
Night Latch : A schematic section through a nightlatch
  • A and B are the door and the jamb respectively.
  • C and E are the body of the latch and the strike or receiver.
  • The white section in the door is a 32mm dia. hole (pretty standard I think)
  • D and J are the separate cylinder and it's escutcheon plate which fits in and over the hole.
  • K is a backing plate and it's screws (green) that mounts the cylinder to the door. This means that the cylinder is separate from the lock fixing wise.
  • H is a meta bar that connects the cylinder to the mechanism of the latchbolt. Which is F
  • G is the knob which also connects with F.
  • The backset is the distance from the edge of the lock/door to the centre line of the cylinder hole.
  • The red dotted lines are fixing screws.

Note! A real trap for beginners. The metal tab H and the fixing screws that come with the lock almost always have to be cut to length (unless you have a really thick door). So you need a hacksaw and clamp on hand to cut them to size. This size has to be accurate! If it is just a touch too long the bar H binds against the knob G and the latch just doesn't work sweetly. Cut it too short and it is back to the store for a new one. "Been there and done that" many times, (Of course I'm a rough old sod... you'll be OK :-)

So look at the lock and the instruction sheet. Don't assume it is the same as the last one that you fixed as they do differ from maker to maker. The old saying "Measure twice and cut once" is never truer than when cutting these fiddly connections from lock bodies to cylinders.

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Please Note! The information on this site is offered as a guide only!  When we are talking about areas where building regulations or safety regulations could exist,the information here could be wrong for your area.  It could be out of date!  Regulations breed faster than rabbits!
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