Any physical security assessment should consider defenses against the full range of potential threats, not just vulnerability to lock picking. If you tried to rotate the plug of such a lock without a key in the keyway, the top pin segment of each pin stack would block the plug at exactly the same number of degrees of rotation; each pin stack would contribute equally to preventing the plug from turning. In an ideal lock, all of the pin holes in the plug would be in perfect alignment with the corresponding holes in the shell, the centerline of the plug would be exactly parallel to that of the shell, and all of the pins would be exactly the same diameter. These locks can be picked according to the same principles as used for ordinary pin tumbler locks, but, again, different tools are used to accommodate the different shape of the keyway. When a key is inserted into the keyway slot at the front of the plug, the pin stacks are raised within the plug and shell. Several positions are possible; here a vertically-oriented torque tool is used at the top of the keyway.

Other classes of attack, not discussed here but at least as worthy of study and scrutiny, include lock decoding, which is concerned with producing a working key based only on access to the external interface of the lock, lock bypass, which aims to unlatch the underlying locking mechanism without operating the lock at all, and forced entry, which, as the term suggests, what is billiards involves the destructive application of force to the lock or its surroundings. Lock picking is a core skill of the locksmithing trade and is also of value to those evaluating, investigating, and studying security systems. Lock picking is useful and worth studying for its generality and simplicity. LAB is a lock pin and locksmith tool manufacturer. Another tutorial reference is The National Locksmith Guide to Picking and Impressioning by Robert Sieveking. It is aimed at locksmith practitioners but has a cogent discussion of principles as well as technique.

It's aimed at working locksmiths, and has a broad discussion of picking techniques and principles, albeit with less depth than the Finch book. The book is an encyclopedic guide to mechanical locks, how to evaluate them, and how to defeat them, aimed primarily at investigators, law enforcement and intelligence operatives. In the lab there is a collection of "training locks," mounted on boards, for practice. However, because the precision with which locks can be manufactured is limited by physical processes, materials, economics, and usability considerations, exploitable weaknesses almost always exist in practice. If you can find a copy for sale, get it. It will take a bit of practice to find just the right technique. Therefore practice different stroke techniques to improve your consistency and accuracy. Note that excessive raking with any of these techniques will tend to overset pins, so be prepared to release torque and start over from time to time.

The lock will never pick open in this state; you must release torque and start over. Repeat until lock turns: - Locate the pin stack that's being pinched at the shear line (it resists slightly when pushed up) - Continue to push that pin stack up until its cut reaches the shear line and the plug turns slightly. The plug/shell border is called the shear line. The plug can rotate freely only if the key lifts every pin stack's cut to align at the border between the plug and shell. Snooker can be even more popular in the UK than pool games in the US. And because those balls were newly introduced into the game, he called his version of "black pool" as a snooker. The most popular version among recreational players is probably eight ball, in which one player attempts to sink all the striped balls followed by the 8 ball, while the other player attempts to sink all the solid balls and then the 8. The first to do so wins.