Bump Hammer Adjustable Weight (Black)

$34.99 $14.99

Locksmiths designed this hammer for locksmiths.  This bump hammer is specifically designed for use in the field.


The Best Bump Hammer on the Market.

Key Features

  • This bump hammer was designed by locksmiths, for locksmiths.
  • The most versatile, all-in-one bump hammer on the market.
  • Unique counter-weight design greatly increases success rate.
  • Hammer head and handle molded as one piece for durability and long life-span.
  • Threaded counter-weight cap ensures counter-weights stay in place while in use.


This bumper hammer is the most important tool you need for lock bumping. You are guaranteed to find the ideal force and follow-through for any type of lock using the adjustable penny weight system. You can apply the right amount of force needed to open a lock with only one tool.

Locksmiths designed this hammer for locksmiths.  This bump hammer is specifically designed for use in the field.

Hammer design features include:

  • Solid molded design to ensure durability
  • Counter-weight cavity sized to be able to use pennies as the adjustable weight
  • Open the counter-weight cap with a coin or back of a key.
  • Scalloped grip that enables you to swing the hammer from as far up or as far back as desired to adjust required follow-through
  • Manufactured with high performance ABS plastic.

All you’ll ever need is the Bump School bump hammer!


Visit the Bump School 101 Blog for additional information about lock bumping.

We also offer many other bump key sets and tools here at our SHOP, including these popular sets!


Wikipedia Definition:

Lock bumping is a lock picking technique for opening a pin tumbler lock using a specially crafted bump key,rapping key or a 999 key. A bump key must correspond to the target lock in order to function correctly.

A pin tumbler lock is composed of a series of spring-loaded stacks called pin stacks. Each pin stack is composed of two pins that are stacked on top of each other: the key pin, which touches the key when it is inserted, and the driver pin, which is spring driven. When the different length key pins are aligned at their tops by the insertion of the correspondingly cut key at their bases, the tops of the key pins and, consequently, the bases of the driver pins, form a shear line, so that the cylinder can be turned, rotating the key pins away from the driver pins. When no key or the wrong key is in the lock, pin misalignment prevents the cylinder from turning.

When bumping a lock, the key is initially inserted into the key way one notch (pin) short of full insertion. Bumping the key inward forces it deeper into the key way. The specially designed teeth of the bump key transmit a slight impact force to all of the bottom pins in the lock. The key pins transmit this force to the driver pins; the key pins stay in place. This physics action can be visualized by observing the same effect on the desktop toy: Newton’s cradle. Because the pin movements are highly elastic, the driver pins “jump” from the key pins for a fraction of a second, moving higher than the cylinder (shear line of the tumbler), then are pushed normally back by the spring to sit against the key pins once again. Even though this separation only lasts a split second, if a light rotational force is continuously applied to the key during the slight impact, the cylinder will turn during the short separation time of the key and driver pins, and the lock can be opened while the driver pins are elevated above the key way.

Lock bumping takes only an instant to open the lock. The lock is not visibly damaged, although the force of the bump can leave an indentation on the front of the cylinder. Certain clicking and vibrating tools designed for bumping can also be used. These allow for rapid repetition of bumping against locks that have advertised “bump proof” features. Only a rare few key-pin locks cannot be bumped.


Additional information

Weight 1 lbs
Dimensions 1 x 1 x 8 in


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