New Picker Question

[wery67564]

OK, so the title of picker may not be entirely appropriate at this point, but I have always been of the opinion that literary embellishments are vital to developing an emotional bond with the audience.

Anyways, my picks haven't arrived yet (yay friday!), but my easy rekey lock arrived today, which made me fall into a series of problems that I hadn't previously considered. When keying a lock, is it necessary to have a matching driver and key pin? I realize that you can get varying tensions by altering the total height of the combined pins in relation to the spring.

How I think about it:

X= driver pin height Y= key pin height Z=Spring compressed height/compression rating/tensile strength (I am not an engineer)

Now, is the X+Y relationship constant?

Is there a relation ship between X+Y being greater/less than some factor of Z that I don't know.

Again, total noob, I have read the CIA lockpicking manual, the complete book of locks and locksmithing and practical lock picking a physical penetration tester's training guide, but have had no real world experience handling actual picks up to this point. Any help on how to key locks would be appreciated...

[zeepia]

When you think about a normal lock, there are different height pins in them. They still normally have all the same springs. If you use a key with that lock, it doesn´t matter how their tension vary from pin to pin. As long as there are space enough for the spring to compress.

You get more complexity in your practice lock when you put some security pins in in.

Some brands make their locks more difficult to pick by putting different springs in them but I think this is minority.

[Squelchtone]

For normal every day picking, the stack height (key pin + driver pin) means nothing and will not affect picking difficulty and wont give you and better or worse feedback as to whats going on the lock.

Most and I mean like 90% of locks out there, the driver pins are all the same size/length, and only the key pins vary to match the cuts (bitting) on the key that makes that lock work. How does it make it work? Well, at rest a lock has springs pushing down on driver pins, which protrude from the lock body into the plug and they press against the key pins which end up all stopping on one of the locks wards or warding.

When a key is inserted the pin stacks move up and down as the key is pushed in further and further, until the shoulder stops of the key prohibit the key from going any deeper into the lock. At this point the key cuts should be directly under the key pins, the key pins should be resting in the cuts or valleys of the key, and if it is the correct key, the tops of the key pins should all be flush with the surface of the plug, and all the driver pins should have been pushed out of the plug and into the lock body, thus compressing the springs evenly in each stack.

Next, the bow of the key is usually used to turn the lock clockwise or counter-clockwise in order to open the padlock, deadbolt, start a card, etc, etc. the plug, on the other side of the lock usually has some sort of cam, tailpiece or other mechanical coupling that then drives the actual locking mechanism, bolt, latch, or what have you. I like to think of the key, and the cuts of the key as being the password or authentication mechanism, if the cuts match the pins inside the lock, the pins all get lifted to the correct height, creating a shearline and since all the driver pins have been pushed out of the plug, nothing is blocking it's rotation, you're basically authenticated at that point, and you can turn the lock and open it.

In picking, we don't have the key which lifts all the pins at once, and we don't have the key bow to use a convenient handle to then turn the lock, so what we have is picks which based on their shapes act as surrogate keys, or individual slices of a key, which allow you to in the case of something like a half diamond pick to raise pins individually or rake under them quickly and try to lift several at the same time in hopes of lifting them high enough to push the driver pins out of the way so they don't block the plug, and in order to create the shearline as if the real key was being used, and in order to turn the lock, we use a tension wrench / turning tool to apply rotational force on the plug so that the pins you lift no longer have a nice straight tunnel to fall back down on, and they bind against the side wall so of the distorted pin stack chambers because the act of inserting the wrench and applying rotational force has made the chamber in which the pins stacks ride up and down a bit angled and the pins start to grind against the side walls and stay up where you want them, until you let go of the wrench and can hear all the pins click down due to the spring trying to extend itself and the pins eventually stop on the warding inside the keyway.

phew, still with me? welcome to lock picking =) I hope that was understandable.
Squelchtone

PS. but wait, what about the other 10% of locks where the X+Z is always the same distance? That's called a balanced stack, and there are several reasons a lock company would do it. One is so the key inserts and pulls out smoothly because the spring pressure is identical for each pin stack. Another reason is to thwart decoding attacks by means of special probes that can go inside the keyway, under each pin stack and measure the heights of the pins in order to then cut a key by code. Two lock mechanisms I can personally think of that use balanced pin stacks is Medeco and ASSA Twin. In Medeco, I believe the pin stacks should always be pinned up/keyed up to equal .5 inches tall.

[Darkness1569]

Welcome to LP101
With basic rekeying I can only think of when you have a really long key pin and a really long driver pin and your key has a high cut on it, like a 1 cut, you might not be able to get the key in or out. It can also kill your spring. But that would probably be a rare event.

[GWiens2001]

Best SFICs', and their clones, also use balanced stacks. I know you know that, Squelch, but just giving another example.

Gordon

[Squelchtone]

Best SFICs', and their clones, also use balanced stacks. I know you know that, Squelch, but just giving another example.

Gordon

Didn't know that, I like SFICs but never pinned up one, so always happy to learn something new. =)

Looking at my Folger Adam pinning kit, it seems those are as well.

Thanks,
Squelchtone

[sandplum]

Schlage has three driver sizes, and Weslock has two driver sizes, depending on key pin size.

[GWiens2001]

There are three different driver sizes on a Sargent I'm playing with. Most keypins are matched with the medium driver, but the 1 bitting depth has a longer one (to prevent overlifting attacks and/or having the driver drop completely into the plug with the key pin), and the 8 bitting depth has a shorter driver (to keep from having too tall a stack, damaging the spring).

You never know, do you? However, probably 90% of locks I see that use driver pins, use the same size in all stacks.

[wery67564]

Wow! Thanks for the help!

Looking at y'alls posts I am realizing that I was thinking of balanced stacks, the schlage rekeyable has about 15 different size driver pins, and 15 different size key pins! I figured that this might be because the stacks should be balanced, which I guess is not necessary, but provides a slightly more secure setting. Since I am keying this lock to be picked, and present varying challenges to me, I probably wont worry about balanced stacks right away.

I also ended up field stripping some locks at I have found, and have kwikset springs that seem to be more tightly wound than the sclage springs. i feel that mixing these up would provide a higher level of complexity as well. But, i am gonna start small and only make it a two pin lock initially.

Again, thanks for the help!