"The Medway Handyman" wrote in message
om...
fred wrote:
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

Anyone seen that Cops with Cameras show? They use the 'big red key' to
batter doors down. Oddly uPVC doors seem harder to knock down than timber
doors.

That is because uPVC doors are much tougher than wooden ones when they are
installed correctly.

They also flex and absorb the shock without breaking like wood does.