11/26/12

 

Lock Picking 101

Part Two

Why Some Locks are Unpickable

       There are however some factors that have the potential for making a lock unpickable. One of these factors would be the existence of a side bar device. This device prohibits the cylinder plug from turning until all the pins are aligned. Sidebars are commonly found in Medeco, ASSA, Primus and other High-Security lock cylinders. These locks are commonly considered “unpickable” by conventional means.

      Another factor is keyway milling, if the keyway is of a complex design it often makes it difficult to freely move the picks up and down in the plug making it difficult if not impossible to pick the lock. Also the cut difference in the key could make the lock unpickable. If there is an extreme variation between two of the cuts on the key, a very deep cut next to a very shallow cut, it can be very difficult to pick both chambers without loosing the shearline in one or both chambers.

       Specially designed top pins or pick-resistant pins are another factor that can make a lock unpickable. These pins have been specially shaped to catch on the shearline when you apply rotational tension. There are several shapes that are used, but each pin design accomplishes the same result.

The Goal of Picking

      Obviously in broad terms the goal of picking a lock is to open it. To be more specific the goal of picking is to lift the pins to same height the key would, there by aligning all the pins along the shearline allowing the cylinder to turn.

       The first thing I like to do and I think most locksmith do in lockout situations is to lubricate the cylinder with a spray type lubricant. This will free the pins and clean the keyway. The better the lock operates the easier it will pick, remember you cannot pick a non-functioning lock. You should test the pin stacks and make sure they all move up and down. You also need to know how many sets of pins are in the lock so you know how many pin stacks you have to pick; most locks have five or six chambers.

       To test the pin stacks; insert a pick upside down into the lock and push it to the back of the cylinder until the tip stops at the back of the plug. Lift the pins as high as possible and quickly draw the pick out. All the pins should drop freely. To count the chambers re-insert the pick upside down into the keyway of the cylinder lift the pins as high as possible and listen as you draw the pick out slowly. Allow the pins to drop one at a time. Count each pin stack as they drop.

      Now that you have determined that the lock is functional and how many chambers must be picked you can begin to manipulate the pins in order to align all the pins along the shearline allowing the cylinder to turn freely.

(Continued in Part Two)

                                                                                                                               11/18/12

Lock Picking 101

Part One

Understanding Locks and Picking

      To understand how to pick a lock you must first understand what makes up a lock and how it operates. After all the goal of picking a lock is to replicate the action of a properly cut key. A lock is basically made up of five different parts. The cylinder plug, the cylinder housing, the springs, the top/driver pins and the bottom pins.

     The cylinder plug is that which the key fits into and rotates in the housing when all the pins are aligned creating the shear line. The shear line is where the cylinder plug ends and the cylinder housing begins.

     The cylinder housing is the exterior shell, which houses the springs, and top/driver pines. The springs hold the top/driver pins and bottom pins down in the plug. The top/driver pins sit on top of the bottom pins and block the plug from turning when they are down, the top pins are down when the key is removed from the cylinder plug. The bottom pins are pointed on the bottom and flat on top, they are sized to fit the cuts in the key and ride in the cuts of the key when the key is inserted in the cylinder plug.

     When the proper key is inserted into the cylinder plug each pin stack is lifted to the correct height. This aligns the top/driver pins above the shear line and the bottom pins below the shear line. This alignment allows the plug to turn freely. Typically there is linkage connected to the back of the plug, which operates the latch allowing it to slide into and out of the striker plate on the doorframe.

     The next thing is to have the basic picking tools starting with picks. There are a verity of different picks for instance the hook pick, the half diamond pick and what I believe most locksmiths prefer the traditional rake pick. A light or medium tension wrench and a spray can of lubricant.

      An important factor in making it possible to pick a lock is known as “Pin Segment Clearance.” Which is the clearance around the pin segments in the plug. This clearance, combined with the hole pattern, is what lets you “feel” the lock as it picks. The less expensive cylinders allow more room for side-to-side pin movement, which makes them easier to pick. To get an idea of how much side-to-side movement you have try inserting a key half way into the lock, and turn the key back and forth easily as to not break the key off in the lock. The play your feel is the lateral side-to-side pin movement.

      Another important factor in making it possible to pick a lock is “Inaccurate Drilling.” When a cylinder plug is drilled during the manufacturing process, the barrels usually are not drilled perfectly straight. This inaccurate drilling causes the barrels to bind one at a time, when rotational pressure is applied with a tension wrench. To effectively pick the lock, you must pick the barrel that binds first. Then you must pick the barrel that binds second, and so on, until all the barrels are picked.

(Continued in Part Two)