A bad lock picker never blames his tools

[3-in-1]

Thanks for describing your key. It is a perfect example of how security can be increased by customizing a lock. Here the capability of the lock is pushed to its limits. And you have successfully increased the MAC from the factory MAC. When I stated in my earlier posts that the factory MAC can't be increased, I was basing that on using "accepted practices". Meaning that the ramp angle of the cut keys and seating area for the pins would remain within factory specs. So the difference here is that although the factory MAC (adhering to spec.) can't be increased, the actual MAC can. We were not on the same page and I should have realized that. But your example also shows why the factory MAC is chosen. In practice, maximum security is usually tempered down for various reasons. For example, reliability can be and usually is, just as important as pick resistance. By having the point of the pin rest on a point on the key, it won't take long for those points to wear down and cause the shear line to drop. In your example the lock rarely gets used, so it works there. So now can we talk about "security through obscurity"?

[unjust]

actually in my lock, the points all rest on ~standard width flats or at the bottom of curves, and while i don't have an original key i'd be very surprised if the prior servicer or original installation didn't pin it in that fashion with a vaugely normally cut key for it. while i haven't yet found specs for the lock (so the acceptable ramp angle *could* be steep enough to allow this biting) i'd be floored if it was w.in macs.

by obscurity do you mean doign things like pinnign with half depth (e.g. 3.5) pins? in general i'm not sure that would significantly increase relative security of the lock. adding in security pins or multiple spring strengths will make picking difficult, but not necessarily any more so than a comparable lock with those features. odd pins shouldn't' affect impressioning (although it seems to have in my case) as best i can tell. now doing things like adding a side pin to a schlage would be fun... hmm i may have my next mill project....

[3-in-1]

I finally was able to cut a 919 on a HPC code machine. Using the recommended cutter for Schlage, I cut the 2 no.9 depths at 1 and 3 spacings first and then checked the height of the 2nd position cut. Once the cutter started to hit the key at the point left between the 2 deep cuts, it was already at a no. 2 depth, explaining why the Schlage MAC is 6. By the way Schlage cuts range from 0 to 9. The key shop had another cutter for this machine that did have a steeper angle and with it I was able to cut a 919 but it left a fairly tiny flat for the pin to rest on. Usuable but not to factory specs so although I was able to increase the MAC it was not an increase of factory MAC. Schlage cuts are at .015" increments and if I chose to use .003" cut increments instead I could increase the MAC by a factor of 5 but again this would not be in spec therefore the factory MAC is not increased. It seems pretty clear that the chosen ramp angle is a compromise between one that remains low enough to give good wear characteristics and one that gives a sufficient number of key changes. It looks like any attempt to go even steeper on the cutter angle would result in the ramping causing too much side loading on the pins. At this point you risk getting the key trapped in the lock if you can even get it in.

[sandplum]

I finally was able to cut a 919 on a HPC code machine.

Unless you plan on limiting your picking to locks in buildings owned by
Ingersoll Rand, I don't know how useful it is to restrict yourself to factory specs. In the real world, it is not uncommon for locks to deviate from factory specs, and for MACS to be violated. In order to become skilled at opening locks that are actually in use, it is helpful to think outside of the box, and outside of factory specs. The only assumption I make about a lock is that the person who installed it wanted to keep other people out. Including the people who think locks have to conform to factory specs.

[3-in-1]

Sandplum, I think you misunderstand. The vast majority of locks in use in this country are to factory specs. And the ones that aren't, are usually the result of someone who lacks the proper training and equipment. It is highly uncommon for a lock to be purposely one off customized. In most cases where a lock is customized, a patent is applied for and the customized lock now becomes a factory standardized lock. Medeco is the perfect example of this. As are all the other tricked out pin locks on the market today. I rely very heavily on assumptions about a lock when I see it. For example I assume that my pin tumbler hooks and half diamonds aren't going to do me a bit of good when faced with a LaGard 2200 wheel keylock or a Kromer Novum lever keylock. And since I made my picks for these locks based on the study of many samples of each model, I assume they will work. And they do. That is not to say that they will work on a one off customized version, but so far I haven't run across one of those.