This tutorial will explain how to open up a master lock with out any additional equipment. All you need is the lock and your head! Also note that this should only be used in the case that you forget your own combination, do not use it for stealing or illegal activities.
Step 1: Get a regular Master Lock, which you already know the combination for. You can later use another lock, for which you don’t know the combo, to test your skills.
Step 2: First goal is the find the last number of the combination. To do this pull down the “U” latch away from the lock. It helps if it’s attached to something (a locker?) While pulling, start to rotate the dial from ‘0’? so you know where to end. You will immediately notice that the dial will stick on certain numbers. You may have to slightly loosen your grip on the “U”? each time it sticks so you can rotate.
Step 3: While proceeding with “step 2”? be sure to note down all the numbers where the dial got “stuck” at. When complete and if done correctly, you should have found 12 different spots.
Step 4: To begin eliminating items, go back and underline all the numbers where the dial stopped in between two numbers. If the dial moved to the left/right of a number, but the number was still in the center leave it in. However cross off all the numbers that were in between two numbers.
Step 5: You should have crossed off 7 numbers, meaning that 5 are left on your list. Now looking at the list you should notice that 4 of the 5 items have the same digit for the one’s place digit. (ex: 05, 15, 25, 35 or 03, 07, 13, 27) Cross off the four items who’s one’s place digit matches with at least one other number’s one’s place digit.
Step 6: The last number you have left should in fact be the last number of you 3-part combination. (ex ?? ?? 25) Now looking at the combinations you now only have 10 possibilities for the first slot and 10 for the second leaving you with a max of a 100 combos to try out. Don’t think that’s a lot because with out the last digit you would have 64,000 combos to deal with.
Please remember that this should only be used for opening up locks for which you have forgotten the password for. And also note that this only works for Master Lock brand locks and doesn’t work on others such as “American” locks because they have a different mechanism.
Here are some downloads to help narrow down the 100 combos:
Downloads: Masterlock.xls (Spread Sheet) | Masterlock.exe (Applications)
UPDATE (01/22/07): New Video Tutorial!