How to Crack a Combination Master Lock

Crack a Master Lock to Recover Its Combination Code

• 1

  Set the combination lock to the "0" position. Create tension by pulling the latch up tightly on the top of the combination lock.

• 2

  Begin slowly turning the combination lock to the right while continuing to pull upward tightly on the latch. You will notice that, as you turn the lock's dial, it will come to a stopping point where you cannot turn it further.

• 3

  Use a pencil and paper to begin your first list of 12 numbers in order to deduce the last digit of the combination. Write down the first number at which the lock stops turning. For example, when the lock stops on a whole number (with the marker on the lock pointing straight at a number on the dial), write down that number. Should the lock stop between two numbers, consider it a half-number and denote it with a ".5." For example, if the lock stops between 9 and 10 as you maintain tension, write down "9.5."

• 4

  Slightly release the tension on the lock and again turn the dial a little bit to the right. Again pull upward with force on the top of the lock and begin turning the dial to the right, noting the number where the lock again stops turning. Repeat this process until you have a list of 12 numbers.

• 5

  Narrow down your initial list of numbers to reveal the third number in your combination. You should have 12 numbers listed, including five whole numbers (without fractions) and seven half numbers ending in ".5." Circle the whole numbers on your list. Four of the five whole numbers should have the same digit in the one's place (the rightmost digit). For example, if you have 15, 25, 35, 45 and 40 as your whole numbers, four end in the same rightmost digit (a 5). Put an asterisk by the number that does not have the same ending digit (in the above list, it would be 40). This is the final (third) number in your combination.

• 6

  Deduce the other numbers in your lock's combination. Using long division, simply take your result from Step 5 and divide it by 4. Circle your remainder or note it as zero. For example, if your result from Step 5 is 40, you would divide 40 by 4, which will give you a result of 10 with no remainder. If your result was 41, you would divide by 4 for a result of 10 with a remainder of 1. Your remainder should be 0, 1, 2 or 3.

• 7

  Create a list of possible numbers for the first part of your lock's combination. Begin a second list of numbers, based on your result from Step 6. Begin the list with your remainder. Add increments of four until you cannot do so any longer, for a total of 10 numbers. For example, if you had a whole number in Step 5 of 41, causing a remainder of 1 in Step 6, your list would read, "1, 5, 9, 13, 17, 21, 25, 29, 33, 37." Your list should not include numbers over 39, since that is the largest number on the lock's dial. The first number of your combination will come from this list.

• 8

  Create a list of possible numbers for the second part of your lock's combination. Add or subtract 2 from your Step 7 list. If your remainder from Step 6 was 0 or 1, add 2 to each of the results in your Step 7 list. If your remainder from Step 6 was 2 or 3, subtract 2 from each of the results in your Step 7 list. Rewrite your Step 7 list accordingly by following this rule. For example, the rewritten list from Step 7's example would necessitate adding 2 because it had a remainder of 1. The rewritten list would then be "3, 7, 11, 15, 23, 27, 31, 35, 39." The second number of the combination will come from this revised list.

• 9

  Begin trying combinations for your lock, using choices from your lists for the first number (Step 7) and second number (Step 8), while ending in your known third number (Step 5). Make sure to run through all possibilities and pull the lock upwards after each combination has been tried. Using the example lists in Step 7 and Step 8, you would try the combinations 1-3-41, 1-7-41, 1-11-41 until you had run through all possibilities beginning with 1. If none worked, you would move on to combinations that begin with 5 and end in 41 (your known third number), such as 5-3-41, 5-7-41 and so forth. Within several minutes, you should have run through all possible combinations, and will have revealed your lock's combination.