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how to set combinations

This video covers the complete process for changing and setting the combination of a 5-button Simplex lock.


For unknown reasons, the full details of how to set combinations with this lock were lost for years—even to Dormakaba, the manufacture. At the time of posting my video (June 23, 2020), no one had yet recorded a proper tutorial for users of the Simplex lock. The YouTube channel for Dormakaba had no detailed tutorial on the subject, and all printed instructions I had found with handgun safes were incomplete. Mine is the first complete tutorial on how to set combinations with a 5-button Simplex lock.

I recommend that first-time users practice setting simple combinations after watching this video, so that the process becomes less intimidating and more familiar. Play with it. These locks are designed to withstand heavy use. You will not harm your lock by setting and resetting combinations.

Setting combinations

How to open a Simplex lock without a combination

Though the owner of a safe fitted with a Simplex lock should practice using the lock, a person could conceivably forget the combination. One might also inherit a safe fitted with this lock and have no knowledge of the combination. In this situation, one would rather not have to cut into the safe with an angle grinder.

Fortunately, there is a way to remove these locks with only modest effort. The video here shows how to do it. The tools I recommend you have are: 1) a ten-inch flat-head screwdriver; 2) a small screwdriver or an awl; 3) a cordless drill, 18V or higher; and 4) a Phillips-head screwdriver. You will need the Phillips-head screwdriver to unfasten the Simplex lock from inside. If the lock also has shielding to prevent the lock from being knocked through, you may need a socket-wrench set. 


how many combinations are possible with a 5-button simplex lock?

The 5-button Simplex lock allows for a total of 2,162 possible combinations. For an understanding of the mathematics, see my video, “How Many Combinations Are Possible With a Simplex Lock?" The video introduces the subject of combinatorics, and offers an easy to understand method for calculating the total combinations possible using the 5-button Simplex lock.


Before I posted this video on June 24, 2020, not a single correct calculation of the total combinations possible using the 5-button Simplex lock had been performed. At least, the evidence was not available anywhere in writing or in video posted online. I had seen the figures 1,081 and 1,082 proposed online, though neither of these estimates were correct.


The second figure, 1,082, was particularly troubling to me, considering that the math instructor who proposed that number included the null combination, which involves pressing no buttons. Properly speaking, if one is not actuating any buttons, one is not actuating any portion of the internal mechanism responsible for releasing the lock from the locked state, and therefore one cannot be said to be "using" a combination to open the lock.


This is not to say that no one was capable of solving the problem. Students of combinatorics and their instructors have had the knowledge to tackle the problem since the Simplex lock was invented. Unfortunately, every attempt to calculate the number of possible combinations had been made by individuals who knew nothing about Simplex locks. Locks were not their field. Math was.

Thus, as a result of being in the right place at the right time, and of having an interest in math (though no degree in the subject), I have had the unique privilege of being the first to present a clear method by which to calculate the total number of combinations permitted by the Simplex lock, and then to share that final figure which has been the subject of speculation for decades.

Number of combinatios possible

is it true that simplex locks are vulnerable to attack with a magnet?

At one time in the early 2000s—before KABA merged with Dorma to form Dormakaba—KABA was facing legal trouble because locksmiths had found that the 1000-Series Simplex door locks could be bypassed using a strong rare-Earth magnet. A critical component of the locking mechanism was made of ferrous material, allowing the lock to be compromised easily and covertly.

However, new Simplex locks like the 9600-Series locks installed in handgun safes are not vulnerable to attack with a magnet. Since I still answer questions about this issue, I have recorded a simple video to reassure people with lingering doubts about the lock. It’s titled, "Can a Simplex Lock Be Opened With a Magnet?"

Magnet attack question
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