I'm not sure if this is an appropriate place to ask this, but I figure the worst that's going to happen is my question will just get closed, so here we go.

I just got my first home defense handgun, a Glock 19 gen 4, and I was wanting to store it within my combination safe. I timed myself at roughly 25 seconds to open the safe and retrieve the gun. This is fast, however, I was wondering if I could make it faster.

Normally you would need to turn the dial like this(Please note i don't count the first 4 turns because that should be muscle memory when opening a safe anyway):

4 times to the left, and end on the first number
3 times to the right, and end on the second number
2 times to the left and end on the third number
1 time to the right and end on 0. (This last step seems to be universal)

What I would like to do is reconfigure my safe to do something like:

4 times to the left, and end on the first number
1 time to the right, and end on the second number
1 time to the left, and end on the third number
1 time to the right and end on 0.

I'm essentially cutting out the extra turns of the tumbler. The concept seems solid, and I can indeed make it to the back of the safe tumbler to see the internals.

My question is, is it possible to change not only the combination, but the way the combination is entered, and skip additional turns? The only downside I can see to this is by overriding the functionality of the safe, I may be decreasing the number of permutations for the combination. I can live with that if it means cutting down the retrieval time of my gun to around 5 seconds, which my concept will likely do.

Is this possible?

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  • $\begingroup$ No, that isn't possible with that type mechanism. $\endgroup$
    – Phil Sweet
    Apr 8, 2018 at 4:07
  • $\begingroup$ You cannot override the behavior of a mechanical device. $\endgroup$
    – paparazzo
    Apr 8, 2018 at 9:14
  • 1
    $\begingroup$ In order to do this, you would effectively have to build your own safe from scratch. There is no way to make a simple modification to achieve your goal. $\endgroup$
    – Daniel K
    Apr 8, 2018 at 12:17

1 Answer 1


You cannot do this with this mechanism. I will now explain in detail how mechanical rotary knob combination lock mechanisms actually work rather than just tell you that you can't.

These kinds of locks are extremely simple, using a series of stacked disks, with a protruding rod on both sides of each disk, and a notch at some random location on each disk.

When you rotate the knob 360 degrees in one direction, the first disk will at some point have its protruding rod make contact with the rod of the second disk. The two disks now move together as a group.

When you rotate the knob a second 360 degrees in the same direction, the knob of the second disk will make contact with the knob of the third disk. The three disks now move together as a group.

This process continues until all disks are moving together as a group. The number at which you are to stop rotating the dial after four turns, will align the notch in the fourth disk with the release lever.

You now need to turn the dial in the opposite direction, so that the protruding pins make contact on the opposite side of each disk, until you are moving all but the fourth disk. You now carefully move the dial so that the notch of the third disk is aligned with the previous fourth disk.

You back out of the number of turns because you are gradually aligning the slots of each disk with the release mechanism, without disturbing the previously positioned disks in the stack.

There is no other way to position the disks other than to gradually back out 4 turns, 3 turns, 2 turns, 1 turn.


Also due to how these disk combination locks work, there are actually two ways to position the disks that will open the lock, depending on if you start by turning the knob to the left or to the right. Though you will normally only be provided instructions for one of these methods, and only by starting the turning in one direction.


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