Divinorum wrote:Thanks phrygianradar. I picked it to control 2 more times so far but, have not found the operating shear line yet. I was under the impression that the control sheer line would be harder to find and that it was usually the top shear line. What I mean by that is that my control key has lower cuts and my operating key has higher cuts. Is it not usually the other way around?
"Because the two shear lines are separated by slightly more than the maximum bitting height of a key, any given cut can only reach one of the two shear positions. Each pin stack must therefore have two sets of cuts -- one for each shear line -- stacked one on top of the other. Each shear line is keyed (and can be mastered) separately, and a key that lines up cuts for some pins at the operating shear line and cuts for other pins at the control shear line will not operate the lock at all. (In this respect, SFIC locks are similar to "master ring" cylinder designs). Note that the bitting of a control key at any given position might be higher, lower, or the same as an operating key; the only requirement is that the complete control key bitting cannot also be used as an operating key"
that is a direct quote from this link
http://crypto.com/photos/misc/sfic/