Everyone is familiar with simple laminated padlocks. Pictured are Master’s models #1 and #3, the most common padlocks in the world. Master makes them by the million. They have many variations – larger, smaller, longer or thicker shackles, all brass for use in corrosive environments, plastic covers, etc. Other manufacturers copy them in large numbers as well.
These locks are a good value and suitable for numerous applications. It is worth knowing their limitations, however. For starters, most have case hardened shackles which are fairly easy to cut. On some Chinese knock-offs the shackles are not hardened at all. Shackles that are completely hardened offer more security.
Another issue is that probably 95% of these locks use the same type key, the Master M1 key blank (or a copy of it). Without getting very technical here, there are only four cuts on these keys, and seven different cut depths. This means that there are only about 2400 possible combinations of cuts – not very many. For comparison, the standard Schlage house key has five cuts and ten different cut depths, so there are 100,000 different ways to cut their keys. In addition, because of the way padlocks are sold into some markets certain combinations of cuts are sold in very large numbers. With only four cuts, locks using the M1 keys are relatively easy to pick open or “bump” open – especially the cheap knock-offs. And there are additional tricks that can make these locks vulnerable to being opened by the wrong people.
If you need a padlock that offers high security there are better choices, by Master and others. Invest a little more money to get locks with more cuts on the keys, with shackles that are hardened throughout, with shackles that are protected from cutting tools or even with lock bodies made from different materials. Go to a good lock shop to learn more and see a wide variety of products.
Note: the names Master and Schlage are registered trademarks.