Master Lock Has A Better Way

June 2, 2009
The new BlockGuard™ spring bolt system shape is flat on the sides, which prevents rotating a shim around the shackle.

Locksmiths and manufacturers have always had an uneasy relationship. By definition, a lock manufacturer is in business to make secure products. By necessity, a locksmith is in business in order to find ways to bypass lock products. There is no hostility on either side, but both sides realize that the stakes grow higher as the years go by and products become more and more sophisticated. Companies such as HPC, Major, Majestic and Peterson Tool have built their reputations by producing tools designed to bypass or open locks.

In some cases a simple lock bypass method is not discovered during the inventing and manufacturing process and this leads to a security issue for manufacturers of that type of product. One good example of that is key bumping. Companies such as Master Lock Company and others spent much time and effort to develop a more secure pin and spring system to deter key bumping. Their new anti-bumping system is now available. There are no outward signs of a change, so people determined to key bump will not know what they are encountering.

Master Lock did not stop with the key bumping issue. The accepted system for keeping shackles locked has been a round, bevelled, spring-actuated bolt. As the shackle is inserted into the padlock body, the spring bolt allows the shackle to pass by, and then the spring-actuated bolt moves into a notch in the shackle to keep the shackle locked in place.

Because of the rounded Master combination lock body, the spring bolt is close to the outer surface of the housing. Clever people in the lock bypass business have found that a short shim can be inserted next to the shackle to access the spring bolt. Depending on the method used, the shim can either be pushed straight downward, or inserted and then rotated around the shackle in order to depress the large round spring bolt. In some cases this procedure allows the padlock to be quickly opened without damage.

Master Lock realized that this procedure compromised the security of their combination padlocks, so they have developed a new spring bolt system called BlockGuard ™. The new spring bolt shape is flat on the sides. This prevents rotating a shim around the shackle. The shim will hit the side if the spring bolt instead of accessing the front of the spring bolt as was previously possible. The shim can move no further and the spring bolt remains locked.

A notch has also been inserted on the top of the spring bolt. If a shim is pushed straight downward, the shim will hit the notch and not be able to be pushed further to depress the spring bolt. Again, the outward appearance of the combination lock will not indicate any changes, but the “shim open” method is blocked. When the shackle is opened, the difference can be easily viewed through the opening in the lock case.

The BlockGuard feature is available on Master 1500, 1502 and 1525 combination padlocks. For more information, contact your locksmith distributor or Master Lock, telephone 800-308-9244 or web site