This may not hold true for all locks, but itвЂ™s been that way for every Dudley lock that IвЂ™ve seen. For almost all Dudley locks out there, the second combination number is lower than the first. So really there are only 100 possibilities.Д«ut in reality there arenвЂ™t even that many. This knocks our possible combinations down 90 percent.

We actually only need the first two turns of the combination to open the lock, because on the third turn you can just spin the dial through each zone while pulling up on the shackle. Well you could sit down and run through 1000 combinations, mind numbing as that would be, but luckily it gets easier. Okay now we have 10 x 10 x 10, or 1000 possible combinations. Each lock will have different sticking zones so the numbers will vary, but there is always a 6 point spread between them. So for this lock we have 2, 8, 14, 20, 26, 32, 38, 44, 50, and 56 for our possible combination numbers. The indentations are always 4 numbers wide, which makes it easy for us to figure out the rest of our combination numbers вЂ“ just keep adding 6 to your first number. There will always be a two number buffer between the sticking points, representing the gap between indentations in each internal disc. The next sticking point will be between 7 and 10. This is the first position of this lock, so take a number in the middle, letвЂ™s say 2. Say you find that the dial sticks between 1 and 4. Now youвЂ™ll be able to see the 10 positions behind the dial, and youвЂ™ll be able to find the 10 numbers the combination is picked from.

Sticking zones (in green) and buffers (in blue) for this particular lock.

Dudley lock serial number database