2009-05-12

Picking Tumblers: Part II

BatmanOk, so you've had way too many days to think about how a pin tumbler lock works.

Lock pickingFirst and foremost know that picking a lock requires TWO (count 'em: two) tools and not just one as you may have been mislead into believing by Hollywood. You need both a pick and a torque wrench.

Picking locks depends on the imperfections in machining the locks. If a lock was made perfectly it could never be picked. But as it stands, the machinists' imperfections mean that the lock has a little give. Remember that the springs pushed the driverpins down and they in turn push the key pins down. When a torque is applied to the plug by a key (or something else, say maybe a torque wrench, perhaps?), the driverpins bind unless lifted to the exact same height as the shearline. BUT (here's the beauty of it all) the holes that are drilled can't be in a perfectly straight line (nothing's perfect - the impression can be as small as 0.0002in but even that is enough). Because of that imperfection, one pin must be first and only that pin is actually binding! The rest of the pins are still loose and free to be pushed up and down. The hull and the plug crimp only that one driverpin in place and stop the lock from rotating.

lock pickinglock pickinglock pickinglock pickingIf you apply a GENTLE torque to the plug with the torque wrench and then go in the keyway with a thin hooked tool (called a hook pick) and push up on the pin that is stuck, you can push until the drivingpin is lifted above the shearline. All, of a sudden the plug will rotate just a bit. If you stop pushing up, you will find that the bottom keypin is free to drop because the drivingpin is no longer pushing on it. When you pushed it up, it passed the shearline and was no longer in the way. Because you were applying a GENTLE torque, the plug turned until the next pin crimped. This created a tiny ledge for the first pin to rest on. You can now move onto the next pin.

If you do this for each and every pin, eventually nothing will be in the way. Once that last pin is set the plug is free to rotate all the way and you've keylessly unlocked it.

Note 1) Gentle was the key word. Gentle GENTLE. GENTLE!!! If you turn the torque wrench too hard you can cause more than one pin to bind. Even metal is somewhat malleable, the pins might give a bit and more than one may bind jamming the lock.

Note 2) When pushing the pins up with the pick, you have to be careful because you want the drivingpin to just barely get above the shearline. If you keep pushing up after that, the pins will rise further and the keypin will bind in the shearline and that's no good. You've got the keypin to bind instead of the driverpin, good job but you still can't turn the plug any further.

Note 3) After setting a top drivingpin make sure that the bottom keypin falls freely. If it stays up, you pushed too hard and you have to relieve some tension from the torque wrench. Don't be surprised if you have to start all over again if this happens.

Note 4) Of course, you can't see what's going on inside the keyway. You have to feel it. Be slow. Be gentle. You have to get a feel for how the pins respond when they are binding, when they are being pushed by a drivingpin and when they have freely fallen on to the ward. You will be able to feel (or maybe even hear) a small click when the top pin is set.

Note 5) Every imperfection in manufacturing is different so the order of setting will always be different for every lock.

Note 6) Some locks have one way that the key must turn. Turn the torque wrench that way. It sucks to work for a long time and then realize that you've just been rotating the plug the wrong way. That happened to me in Pittsburgh.

Note 7) Locks are often outside or other places where the elements can degrade them. Grease and dirt often clog the lock cylinder. Cleaning the lock with gasoline or WD40 or something can really make your job easier.

BatmanIf you're interested in this you might want to check out "Unauthorized Entry and Physical Security Collection"(torrent), a torrent that can be found on many archives. Also, the online MIT guide is good. And never skip a wiki-type introduction. Personally I used the book "Visual Guide to Lock Picking" but having now successfully picked a couple of locks, I can whole heartedly agree with the author, Mark McCloud, who repeats again and again that what you need is practice and not being an author who makes anything from my writings, I can say what he probably really wanted to: "You don't need a book. Just a lock-pick set, an old lock (surprisingly door dead bolts are easier than pad locks) and maybe some helpful hints like I've tried to give on this blog or like you can find on YouTube."

Visual learners should definitely check out YouTube tutorials. The first ones to come up are like Simple Lock-Picking Guide, Whiteboard masterlock lockpicking tutorial basic how to pick or Lock picking tutorial.

No comments: