5 lever locks (mortice/mortise)

[Fortress]

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!

[Catlocks]

Some manufacturers use the system where 3 of the cuts are used from both sides of the door. so even though there are only 4 cuts running from the centre of the key the cut before the centre is used so your levers would be for e.g 43421 giving your 5 levers.

As you say you have just moved into the house I would suggest changing the locks. You dont know who has hand keys cut for the house. Also for insurance purposes you will need 5 lever BS3621 on the final exit door.

Depending on the make and model of the locks a Locksmiths would be able to change the levers and keys this can sometimes be cheaper than buying a new lock ( Chubb would be a good case for this saving about £15 )

Hope this helps and any other questions just ask.

Wayne

[Fortress]

Thanks for your help Wayne. I have changed 2 of the locks (back & patio) with BS3621 locks. The lock in question is an ERA 5 lever. After I didn't get any responses here for more than a week (maybe you were on holiday!), yesterday I found locksmiths101.com so I repeated the questions there.

Then I found your response here. Thanks again, Sir Catlocks, you're very generous.