Lever 1 or 5

[chrisjc33]

When you take the cap off a mortice lock is the top lever 1 or 5(or7)?
On reading about locks some call it lever 1 and others lever 5.It's been bugging me

[EvoRed]

On the Safeventures pin and cams the lever nearest the bolt is marked up as number 5.

[pinky]

in general most refer to the lever nearest the bolt being lever 5, so as you remove the case plate you are looking at lever 1

[nicholls]

I've never really called them by number, i always refer them to top to bottom, but in general the top is lever 1 and the bottom one (nearest the bolt) is lever 5, in most 5 lever locks (if not all) levers 3 & 5 are the same to keep the key symetrical, and to keep the lock in question to exhibit over 1000 keying combinations.

[pinky]

Not all 5 lever locks have this 5 and 3 lever the same, all 7 cut keys do, but all 9 cut keys dont, such as , chubb 110 , securefast and walsall, this offers far more differs, for instance the chubb 3G110 with having a 9 cut key and 9 lever heights this lock has 25000 differs, having a 9 cut key and not following the lever 5 and 3 being the same rule drasticaly increases the differs, ie again, the securefast only has 5 lever heights, but by having a 9 cut key it attains the required 1000+ differs.
The only way to drasticaly increase differs other than having a 9 cut key is to increase the number of different lever heights.

[nicholls]

Forgot about the symetry!! I guess the 9 cut keys rely on lever 4 being the centre for the keys symetry??

[pinky]

the cut for lever 5 nearest bolt is the only cut used on both sides of door.

[nicholls]

Sorry yes it was lever 5 as in the 9 cut key: 4-1-4 symetry

rather than a 7 cut keys: 2-1-1-1-2 symetry