Transfer Students

Learn Why and How to Transfer Mechanical Combinations

by Jeremy Reeder, Certified Journeyman Safecracker

Copyright (C) 2009 The Safe House. Originally published in Safe & Vault Technology, Volume 24, Issue 4, May 2009.

When we safecrackers deal with mechanical combination locks, sometimes we determine a combination while dialing to one index and then transfer that combination to a new index. In this article, I'll address how and why we do this.

Why transfer?

We do it because we can see the lock's wheels but not its fence. If we could see the wheels and the fence at the same time, we'd simply align the gates of the wheels with the fence and unlock the safe. Which, on the surface, seems more appealing, doesn't it?

Let's say you intend to drill at a location that allows you to view the fence as well as the wheels. This is a sensible and common goal. Then, when you finish the hole, let's say you can see the wheels but the fence is nowhere in sight. What now? You were obviously wrong about the location of the fence, but that's okay. Through combination transference, you can make multiple guesses at the fence location and easily try them all out. You don't have to drill any additional holes to do this, so the safe will be open in no time. Transferring is cool like that.

The funny thing is that we sometimes choose to drill a hole in a place that doesn't let us see the fence, thereby requiring ourselves to transfer the combination we find. I do this frequently, simply because the location of the fence is usually a very minor consideration for me. The fence is often above the wheelpack, and I usually place my drill points below the wheelpack. This way, I avoid depositing drill shavings into the wheelpack through the hole I drill. When I get debris between wheels, the wheels stick together, which sucks monkeys. (More specifically, it causes a wheel to transfer motion to another wheel even when the former's drive pin is not in contact with the latter's fly. This makes it very difficult to properly align the wheels.)

How to transfer:

When we can see an edge of the lock's wheelpack through a drilled hole, it's easy to turn the dial knob and note which combination aligns the gates of the wheels at that hole. If you can do this, you can transfer the combination to align the gates at the fence, thereby unlocking the safe. Relax, dude, it's a piece of cake.

The procedure of determining a combination and transferring it to the fence is as follows:

  1. Drill a hole somewhere around the circumference of the wheelpack. Sometimes it's convenient to drill through the dial ring and keep the dial intact. Other times it makes more sense to remove the dial and ring to drill beneath them. Cutting the dial off of the dial knob with a hole saw and then drilling under it is another option. It's your call. See the drilled holes in figures 1 and 2, respectively containing a borescope and a drill bit.
  2. If, in step 1, you left the lock's spindle with a dial or at least a knob attached, then you're set. If not, attach some kind of knob or dial that does not obscure the hole you drilled. (See the small little 1.5_in “emergency dial” pictured in figure 1, fastened to the spindle with two allen set screws.) [Note: For this purpose, it makes no difference whether the dial is aligned with the spindle in the same way the original dial was. So don't worry about that. In fact, it doesn't necessarily even need to have numbers or markings of any kind, but I prefer numbered dials.]
  3. Determine a combination that aligns all the gates at the drilled hole.
    1. If the dial is marked with numbered graduations and is front-reading:
      1. While viewing wheel #1 through the hole, turn the dial in whichever direction the lock's operating instructions specify.
      2. Stop when the center of the wheel's gate is aligned with the hole.
      3. On the dial, note which dial graduation is aligned with the hole. This is the first number of a combination that would align all wheels at the hole.
      4. Reverse the dialing direction and move on to the next wheel.
      5. While viewing the next wheel through the hole, turn the dial until the center of the wheel's gate is aligned with the hole.
      6. Note which dial graduation is aligned with the hole. This is the next number of the combination that wil align all wheels at the hole.
      7. Repeat steps 3.1.4 through 3.1.6 until you run out of wheels in the lock.
    2. If the dial/knob has no numbers or is obscured by a spy-proof dial ring (as in figure 2):
      1. While viewing wheel #1 through the hole, turn the dial in whichever direction the lock's operating instructions specify.
      2. Stop when the center of the wheel's gate is aligned with the hole.
      3. Mark a graduation on the dial, aligned with the hole. Label the graduation “1” to correlate it with wheel #1.
      4. Reverse the dialing direction and move on to the next wheel.
      5. While viewing the next wheel through the hole, turn the dial until the center of the wheel's gate is aligned with the hole.
      6. Mark a graduation on the dial, aligned with the hole. Label the graduation according to the wheel number.
      7. Repeat steps 3.2.4 through 3.2.6 until you run out of wheels in the lock.
      8. The combination is simply an ordered sequence of numbers: 1-2-...-n, where n is the number of wheels in the lock and the numbers in the combination correspond to the marks you've made on the dial.
  4. Transfer the combination to a new index. (The current index is the drilled hole. Note that the combination you found could be dialed to any index, and that dialing it to any given index will align all of the gates at that index. Remember that the goal is to align the gates with the fence.)
    1. Determine the location of the fence. If you don't know, guess.
    2. On the dial ring, mark a “fence index” denoting the angle at which the fence is located.
    3. Dial the combination to the fence index and see if it unlocks the lock.
    4. If the combination does not unlock the lock when dialed to the fence index, guess a new fence location and repeat steps 4.2 and 4.3.

Offsetting – the mathematical approach:

Rather than transferring a combination from the drilled hole to the fence, some safecrackers use a mathematical approach that I call “offsetting”. They use the 12-o'clock opening index exclusively. Rather than transfer the combination to a new index, they alter the combination through arithmetic. That is, they offset a combination by adding to or subtracting from each number in the combination. Adding 25 to each number, for example, has the same effect as transferring the combination 90 degrees counterclockwise.

It works, but I advise against this method. It's not very complicated, but it's more complicated than it needs to be. I find it surprisingly easy to mix up whether I should be adding or subtracting. The same mistake has been made by other good safecrackers, both on the job and in published works. This simple mistake can waste a lot of time, so I favor the non-mathematical approach.