Kromer 3065
On the first two photos it looks very normal. No protection against manipulation at all. But on the third photo you see its special feature: two flies per disk. The effect for the user is that the combination is dialed as 2L, 1R, 1L, R to stop. Verrrry convenieeent! After one full turn you are guaranteed to move W1, because after at most 20 numbers you catch W3, about the same more and you get W2 and 40 to 50 more and you have W1. The contact points can be read easily. The pickup of W3 can be heard too. I can't feel or hear the pickup of W2 and W1 without tools. Not yet tried with a mic. So while the basic mechanisms of manipulation work quite well with this lock and the range of possible combinations is not that big it is quite difficult for me to determine which wheels I move. Because I can only guess from one sample I do not know if the possible rotational range varies from lock to lock. From what I see I can "only" say that W3 is between W2 and W1 and within 20 numbers above the RCP, that W2 is below the RCP and W1 above. In this lock the lever was twisted, so I can't say how big the shift of the CPs generally is. In this lock it is about a 3/4 number for W1 on the LCP, which looks to me more interesting.
Do you know any other locks with double flies?
Martin Hewitt, Investigator Chronicles of Martin Hewitt