In article ,
ARWadsworth writes

"fred" wrote in message ...
In article , John
writes
I just wondered why Yale locks were always fitted at eye level but
mortise
locks were fitted half way up the door (traditionally)

The most common and vicious form of attack for a door[*] is kicking-in
so it makes sense to keep the strongest protection at waist height or
below. If using 2 reasonable locks as you describe, I'd have the mortice
at just above knee height and a deadlocking cylinder just below shoulder
height.

Having the mortice half way up isn't that great an idea as it leaves a
bit too much spring/flex in the lower part of the door making it a weak
point.

The top cylinder on its own is just to stop the wind blowing the door
open.


[*] Unless it's with a sledge hammer

Not many people try that sort of thing though;-)

There was a spate of it a good few years back, top floor tenement flats
(least likely to be disturbed) with the door taken out by a sledge
hammer. My mate's place got done that way, the neighbours heard the
noise but assumed it was someone with the builders in. Since then I've
taken that kind of attack into account when designing my lock layout,
it's also why I have a shock sensor on the door frame with a v loud
sounder beside it.

I think I'm pretty safe now unless some big sparkie takes a run at my
door ;-)
--
fred
BBC3, ITV2/3/4, channels going to the DOGs