Antibumping

Antibumping is a security feature commonly found in modern pin tumbler locks. Its primary purpose is to prevent or at least significantly hinder a common method of lock picking known as "bumping." Lock bumping involves using a specially cut key, called a bump key, inserted into the lock and then struck. This impact temporarily aligns the pins, allowing the cylinder to be turned with a slight twisting force.

The antibumping mechanism typically consists of one or more specially designed pins, often referred to as security pins or mushroom pins. These pins have irregular shapes that can catch or interfere with the upward movement of the standard pins when a bump key is used. When the lock is struck, these security pins prevent the clean, single-line separation of the key pins and driver pins that is necessary for successful bumping. Instead, they create a jagged or incomplete separation, making it difficult or impossible to rotate the cylinder.

While antibumping features are a significant deterrent to lock bumping, they are not always foolproof. Highly skilled or determined individuals may still find ways to bypass them, or they may target locks without antibumping technology. However, for the average user, the presence of antibumping pins greatly increases the security of their locks against this particular attack vector. Many modern locks are manufactured with antibumping features as a standard component to offer enhanced protection.