We've just moved into a new house. I think I read somewhere that for a door that can be opened from either side, the number of levers has to be odd.
Looking at a key, I can't see the profiles for 5 levers, only 4? Three to one side, then a common one in the middle, then 3 to the other side which are the same as the first ones but in reversed order.
So the heights/lengths of the profile go: 1 2 3 4 3 2 1 - see what I mean? Surely that's only 4 unique cutouts?
Question 2: Suppose some cutouts are the same length as their neighbours, so you get like 1 2 2 4 2 2 1, or even 1 222 1 - surely that's insecure?
Question 3: One of our keys goes 1 2 333 2 1 yet on the face of the lock on the edge of the door it says "5 Levers". Just how many levers does this one have then? And with 3 adjacent levers/cutouts all the same, surely this one is very insecure?
Hope there's a few locksmiths on this forum!