In article , The Medway
Handyman writes
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.

I nearly made a comment about big fat coppers not being able to lift
their hammers above waist height but thought better of it.

A UPVC door will likely have multipoint locking so will resist a
moderate impact attack better, the door and frame will also deform
elastically, absorbing some of the impact so will be harder to knock in
but it will be far more vulnerable to levering/jemmying attacks just
because it is plastic

In contrast, a wooden door will rarely be installed 'properly', it wont
be multipoint locked, the frame wont be reinforced to resist splintering
on impact and the door wont be reinforced around the (cheap) locks, also
if it's a pretty panelled door then it wont stand a chance.

In extremis though I reckon I can make a wooden door and frame more
secure than a plastic one but few pay what it would cost to do it.
--
fred
BBC3, ITV2/3/4, channels going to the DOGs