Finding Combinations for  the Master Locks with Serial Numbers Beginning with 800, and for Locks from Other Manufacturers
This is a general purpose method for finding combinations for three number combination locks with a single dial, including the "new" Master locks, ACE Hardware locks, American and Dudley combination locks. The method applies to locks with dials numbered from 0 to 39, like the Master locks. This method assumes that the lock allows for sloppiness when the user dials the known combination. The lock should always open in 340 tries or less and, in about half the time, 170 tries or less. However, we have added an advanced technique for locating the first number in the combination. After the first number has been located this way, the lock should open in 17 tries or less.

This method will produce a combination for a right-left-right dialing sequence, even if the manufacturer's combination uses a left-right-left sequence. At the end, we will tell you how to apply the method to locks with dials are not numbered 0 to 39.

If you haven't already, first please read and practice the method for finding combinations for the locks which open using our method. You will need to be able to locate "sticking places." You will also need to know the method of dialing combinations that "saves on the fingers."

If you have not learned those techniques, please click here to go to the procedure for opening the "old" locks.

Outline of the method

Locate one or more "test" sticking places.

Dial each of the possible first and second number pairs in turn, using the method that "saves on the fingers." (Later, we apply the advanced technique, to start with the correct first number.)

Use a "test" sticking place to determine if you have the first and second numbers correct. If the "test" sticking place is at the correct last number, the lock will open. However, if the test sticking place is at a fake last number, the "feel" will be different, so you will know that the first two numbers are correct. Then, you dial each of the "test" sticking places in turn, to locate the third number and open the lock..

We suggest that you first practice this method on a lock with a known combination and fake sticking places. The practice lock can be one of the "old" Master locks.

Practicing finding "test" sticking places

Start by turning the dial around twice, on the practice lock, and stopping at the correct last number. Pull hard on the shackle and rotate the dial back and forth between the two places where it stops. (If the lock is locked to something, just pull hard on the body of the lock. If the lock is loose, it is helpful to hang the lock over a heavy hook that is firmly anchored into a beam, and pull on the body of the lock.) Notice that the dial turns freely and is no harder to turn when the shackle is pulled hard as when the shackle is pulled lightly. Now, turn the dial to a fake sticking place. Pull hard on the shackle and turn the knob back and forth. Does the dial turn just as freely as it did at the correct last number? If not, that sticking place is not a good "test" sticking place, but you may be able to use it, anyway. Try the other fake sticking places and try to find one fake sticking place where the dial turns just as freely as at the correct last number, no matter how hard the shackle is pulled.

On some locks, the dial will turn freely only at the correct last number. If so, for the lock where you don't know the combination, that is fine, the correct last number is the best "test" sticking place. However, you need to practice on locks that have more than one sticking place where the dial turns freely, so you can learn how to use a fake sticking place to determine if the first two numbers have been dialed correctly.

Now, dial the first two numbers in the combination normally, but stop at the fake sticking place that you found, instead of the correct last number. If you did not find a fake sticking place where the dial turned freely, use any fake sticking place. Pull hard on the shackle and rotate the dial back and forth. Notice that the dial is harder to turn when the shackle is pulled hard, than when the shackle is pulled lightly. Also, the dial may not turn as far, back and forth between the places where it stops, as it did before.

Practice detecting the difference in "feel" at the fake sticking places before and after the first two numbers have been dialed correctly. You will be using that skill later to tell to detect when you have the dialed the correct first two numbers in the combination. Practice at the other fake sticking places, so you develop your ability to detect when you have dialed the correct first two numbers. If you can practice on more locks, all the better!

Finding "test" sticking places on the lock with unknown combination

Use the skills you developed on the practice lock to find "test" sticking places on the lock with unknown combination. In general, sticking places where the dial turns freely, no matter how hard the shackle is pulled, are best. However, you may still be able to detect that the first two numbers are correct, even if the dial doesn't turn freely when the first two numbers are wrong. With good practice, you will be able to notice that the dial is harder to turn after the first two numbers have been dialed correctly.

If you can find several good "test" sticking places, all the better. It will cut down on the amount of dialing you need to do in the next step.

In the next step, we dial possible numbers for the first and second numbers in the combination. We use the "test" sticking place(s) to find out if we have the both first and second numbers right. If the 'test" sticking place is at the correct last number, we are lucky and the lock will open. However, we don't expect to be so lucky. If the "test" sticking place is at a fake sticking place, we should be able to notice that the dial is harder to turn once we have the first and second numbers correct. Then, we try pulling the shackle at all the sticking places. Since one of them is the correct last number, the lock will open.

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