Overview of How Locks Are Disassembled

Posted by on May 27, 2015 in Locksmith

lock was manipulated

determine how the lock was manipulated


Common lock discussions involve materials used, different components, brand names, and installation, as well as repair. However, the way locks are disassembled is seldom part of conversations. Learning about disassembling locks is just as important as everything else, especially for people who provide forensic locksmithing services.

For this specialized career, every component of a lock is examined. For instance, if a home was invaded and entry made by manipulating a locked door, a forensic locksmith would have the responsibility of taking the entire unit apart for examination. This would be followed by another examination in a laboratory setting to determine how the lock was manipulated and possibly the tools used.

Using Extreme Caution

Unlike an emergency lockout situation whereby a locksmith would simply bump or pick the lock, if an intrusion is suspected, the lock must be removed differently to protect possible evidence. For instance, when gaining entry to a locked home where a crime has been committed, all evidence must be preserved, including components within a locking mechanism.

The most important factor is that all cylinder components need to be kept in their original position, order, and alignment. To accomplish this, a trained forensics locksmith uses a pinning tray to organize components after the lock is out. However, for a lever or wafer lock, components would be laid out according to position and order.

Only after the entire cylinder has been removed would the locksmith begin to disassemble it. The primary reason for this is that clues can be obtained pertaining to the method of entry and tools used if the lock is still mounted. This allows the locksmith to examine the lock against the door itself, as well as other surroundings.

Methods of Disassembly

Depending on the type of lock and the situation, a locksmith will choose the most appropriate method to disassemble it.

  • Rapping – With this, a pin tumbler cylinder can be opened without causing damage to internal components of the lock. Somewhat similar to key bumping, this consists of an application of light torque to the cam or plug using one hand. With the other hand, a rubber mallet is tapped gently on the bottom portion of the cylinder. The benefit of rapping for forensics is that no evidence is left behind.
  • Shimming – Another way in which a lock is disassembled is with shimming. This too will not cause damage when opening a pin tumbler pin. For this, a thin piece of metal separates the pin pairs at the shear line. Compared to rapping, this is a slightly more invasive process, but if performed by a qualified locksmith, it will not leave any evidence behind.

In addition to nondestructive methods used to disassemble locks, there are some considered destructive. Because these methods can cause damage at the vivisection of the components, the very area that provides the most forensic information, they are used as a last resort.

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