Using Lock Picking Techniques to Recover Combinations for Master Locks with Key Cylinders

To recover the combination for a lock with a keyhole, it may be faster to pick the lock cylinder and use the methods on our open locks page to recover the combination.

American locks with key cylinders can be picked similarly to Master locks. We found our one American Lock easier to pick than any of our Master locks. However, we weren't able to use our combination recovery methods for open locks on our American lock. Lock picking was simply a way to open the lock.

The video demonstrates how to pick the lock cylinder.









There is a wealth of information on the internet covering lock picking techniques. We find that the "MIT Guide to Lock Picking," renamed simply "Guide to Lock Picking" is a well written tutorial and good starting point. The "Guide to Lock Picking" is credited to MIT (Massachusetts Institute of Technology) students who developed and used lock picking skills to gain access to off limits portions of the university, specifically roofs and tunnels. It is not an official publication of MIT so an effort has been made to remove MIT from the title.

Here is some information for picking this specific lock.

1) The cylinder in this lock has four pins. Some sites refer to this lock as a good practice lock because they claim that it is easy to pick. However, do not expect your lock to open anywhere near as easily as the lock in the video!

2) On a well worn lock, the pins generally bind from back to front. Because the key is rarely used to open this lock, the cylinder will have very little wear. For lock picking purposes, treat the lock as a new lock, where the pins may bind in any order.

3) Both the Master and American lock unlock in the clockwise direction.

4) The tension wrench in a general purpose lock pick set may be too large for this cylinder, but the picks should fit. We made a small tension wrench from metal strips that are part of some automobile windshield wiper blades. If your wipers are due for replacement, install the new wipers and check the old wipers for the strips. You may also find old blades in trash containers outside auto parts stores, especially after a rain storm has prompted drivers to replace their windshield wipers. Another suggestion is to ask employees of shops which replace blades to save old blades for you.

We also found the strips in new Trico wiper refills, but these refills may not be readily available. For many cars, the refill blades must be shortened and there are 4 leftover short metal strips. Bend the metal at a point away from a break score using two pairs of pliers to form a 90 degree bend.

5) In the video, the lock picker appears to be using a technique called "scrubbing," described in the Guide to Lock Picking. We have had better luck using a rake pick.

6) Once the lock opens, do not release the tension wrench. You will need to use it to hold the lock cylinder fully clockwise, permitting the cams to be viewed through the shackle opening. For now, just tape the tension wrench to the lock body, with the cylinder turned a small amount. Proceed to the page describing how to recover the combination for an open lock:

Recovering the combination for an open lock

Key Cylinder Lock Security Concerns

The lock cylinder represents a security weakness. As shown in the video, a skilled lock picker can have the lock open in less than a minute. Furthermore, any lock from the system can be disassembled for purposes of making a key that opens all locks in the system. There are also ways to make a key after picking the lock, making it unnecessary to disassemble/destroy any locks. It is also quite possible that a key from another small padlock from another manufacturer will fit the keyway and just happen to open this lock.

Suggestions for Users

If you and other users are concerned about the security of your personal belongings protected by a combination locks with key cylinders, request to use your own locks, with the provision that you will provide combinations or keys to the administrators so they may still conduct locker inspections. If they refuse your request, assemble a group of concerned users and arrange a meeting with the system administrators. If there have been incidents of items taken from lockers without evidence of forced entry, this is a good time to act, but it is better not to wait. Alternatively to using your own locks, request that the same locks be used, but with the key feature disabled with Super Glue. The system administrators can still conduct locker inspections by consulting tables of combinations by lock serial numbers.

Show the above lock picking video to the system administrators. If the video is questioned, do not demonstrate your ability to pick the lock. Instead, enlist the aid of a professional locksmith in your community to support your case. Someone in the group may have a parent, relative or friend who is a locksmith and willing to help without charge or for a nominal fee.

Suggestions for Administrators

To provide a higher level of security for users, we suggest that you disable the key feature with Super Glue. The downside is that opening the lockers for cleaning and lock reassignment at the end of the school year is more time consuming.