MASTERLOCK COMBINATION RECOVERY
There's a lot about this on the web. To me, I found a way that is easiest and less time consuming to recover a combination. Here's an overview. I couldn't find anything anywhere about the sticking points for anti-shim locks, so I made that method up. It works.
THE SPREADSHEET
Download the spreadsheet. There are two worksheets, one for classic (older) locks, and one for the newer anti-shim locks. The cells in yellow are where you enter in values. You don't have to touch any of the other cells. On both sheets is sample data that I entered from actual locks that I did not know the combination to. You can see the patterns that led me to figuring out the combination.
masterlock_combo.xls | |
File Size: | 46 kb |
File Type: | xls |
FIND THE FIRST NUMBER IN THE COMBINATION - "OPEN SHACKLE METHOD" (IF THE LOCK IS UNLOCKED OR SHIMMED OPEN)
With the lock open, rest the shackle in the shackle hole, but don't lock it. Slowly rotate the dial CCW, and you will see the shackle rise and fall at a certain number on the dial. Do this a couple times until you get used to how it feels and watch the number it falls on. Enter that number in the spreadsheet in the yellow cell to the right of the one labeled "Digit on Dial Where Shackle Falls CCW," and the spreadsheet will tell you the first number. All the spreadsheet does is add a number to the number that the shackle falls back down on. I found this number to be 5 for classic locks, and 2 for newer anti-shim locks. This will give you the first number in the combination.
IF THE LOCK ISN'T UNLOCKED
1A ) Classic Master Lock - Shim the lock open. Google "aluminum can lock shim." This takes less than a minute after you know what you are doing and eliminates more than 50 combinations that you would otherwise have to try.
1B) Anti-Shim Master Lock - If you cannot shim the lock, it may be a new "Anti-Shim Model." In this case don't worry about trying to shim it open. Shimming these locks is hard so don't bother. You will just have to try more combinations since you can't easily find out the first number. Just go to step 2 below and the second sheet in the Excel doc.
1B) Anti-Shim Master Lock - If you cannot shim the lock, it may be a new "Anti-Shim Model." In this case don't worry about trying to shim it open. Shimming these locks is hard so don't bother. You will just have to try more combinations since you can't easily find out the first number. Just go to step 2 below and the second sheet in the Excel doc.
FIND THE LAST NUMBER IN THE COMBINATION
2A) Classic Master Lock - Download and fill out what you can in the spreadsheet. Columns "C" and "D" are where you enter the sticking point ranges. Find these by pulling up on the shackle and rotating the dial CCW and noting the range where the dial "sticks" while still pulling up on the shackle. I enter them in the spreadsheet in increments of 0.25. The sheet will help you find the 12 "sticking points" by showing the digit in the middle of the sticking point range, and the size of the range. If the number in the middle of the range ends in 0.5, then it is not a number in the combination. There will usually be 5 ranges that center on one of these "0.5" numbers, so that eliminates 5 of the 12 possible last digits. The range that is centered on a whole number (or closest to a whole number) will be possible last digits of the combination.
If you are lucky, the "Last Combo Digit" column will only have one green value. If not, you need to look again at the sticking points or look at the 2 columns to the left of that and find some patterns.
2B) Anti-Shim Master Lock - Download and fill out what you can in the spreadsheet. Columns "C" and "D" are where you enter the sticking point ranges. Find these by pulling up on the shackle and rotating the dial CCW and noting the range where the dial "sticks" while still pulling up on the shackle. I enter them in the spreadsheet in increments of 0.25. The sheet will help you find the 12 "sticking points" by showing the digit in the middle of the sticking point range, and the size of the range. If the number in the middle of the range ends in 0.5, then it is not a number in the combination. There will usually be 5 ranges that center on one of these "0.5" numbers, so that eliminates 5 of the 12 possible last digits. The range that is centered on a whole number (or closest to a whole number) will be possible last digits of the combination.
This is a lot more involved with newer locks. There are two sets of false gates. Look for a pattern. The sticking point with the largest range is usually the last digit.
If you are lucky, the "Last Combo Digit" column will only have one green value. If not, you need to look again at the sticking points or look at the 2 columns to the left of that and find some patterns.
2B) Anti-Shim Master Lock - Download and fill out what you can in the spreadsheet. Columns "C" and "D" are where you enter the sticking point ranges. Find these by pulling up on the shackle and rotating the dial CCW and noting the range where the dial "sticks" while still pulling up on the shackle. I enter them in the spreadsheet in increments of 0.25. The sheet will help you find the 12 "sticking points" by showing the digit in the middle of the sticking point range, and the size of the range. If the number in the middle of the range ends in 0.5, then it is not a number in the combination. There will usually be 5 ranges that center on one of these "0.5" numbers, so that eliminates 5 of the 12 possible last digits. The range that is centered on a whole number (or closest to a whole number) will be possible last digits of the combination.
This is a lot more involved with newer locks. There are two sets of false gates. Look for a pattern. The sticking point with the largest range is usually the last digit.
TRY SOME COMBOS
3A) Classic Master Lock - Since you now have the first and last number of the combination and the spreadsheet is filled out, there will be at most only 10 full combinations to try. These are in the table at the bottom of the sheet. Usually there aren't more then 7 combinations to try. Entering 7 different combos doesn't take long at all.
3B) Anti-Shim Master Lock - Try them all.
If this is your first time doing it, it may take awhile. The hardest part is eliminating the sticking points. That is why I made the spreadsheet. All it does is add some educated and solid mathematics to save time. The spreadsheet is a very powerful tool and saves if you use it correctly. It may sound unbelievable, but using this sheet, I have opened a lock with the first combination that I tried. The chances of that happening are less than 1 in 10 if you know how to use the spreadsheet and work the lock.
3B) Anti-Shim Master Lock - Try them all.
If this is your first time doing it, it may take awhile. The hardest part is eliminating the sticking points. That is why I made the spreadsheet. All it does is add some educated and solid mathematics to save time. The spreadsheet is a very powerful tool and saves if you use it correctly. It may sound unbelievable, but using this sheet, I have opened a lock with the first combination that I tried. The chances of that happening are less than 1 in 10 if you know how to use the spreadsheet and work the lock.