this is only minor - near the end pinky states that bs3621 locks all have false notchs. This is not correct, chubb 3g114 has eight levers with the 5 stamped in one corner (this is to tell you that you have a 5 lever - lever?!) and another number that corresponds to the cut i.e 5 - 4 for a four cut and say 5 - 7 for a seven cut.
However they also produce three "extra" levers these are 5 - A, 5 - B and 5 - C stamping. These levers are in fact the same levers as 5 - 1, 5 - 2 and 5 - 3 but have no notch in them! Why is this?
Well imagine having the lock in your hand locked and forcing the bolt back with it while turning the correct keyin the other - what potentially happens is that the bolt would bind in the false notches as the key lifts the levers and it would not open. Hence chubb always put in either a "A, B or C" lever in there locks that does not happen to have a false notch to prevent the bolt from binding in the false notches witht the correct key.
Why use cuts 1, 2 and 3 or A, B and C beacuse these are the highest cuts (obviously) and have to "move" the greatest distance - all the other levers should be in "place" when it comes to this lever gate lining up to the talon if that sort of makes sense
Useless infoi know. Sorry about being away for long time.
will try to post more - except if someone asks to pick a pin tumbler lock that gets repetitive