Don’t believe me? Well okay, it’ll probably take longer than that the first couple of times. But it really isn’t difficult to get the combination for a Dudley you’ve never seen before.

At first it seems like an impossible task. You’ve got 60 points on the dial and you need 3 turns to open the lock. That’s 60 x 60 x 60, or 216,000 possible combinations. Theoretically.

What helps us out here is that each and every number isn’t used, since the internal discs are not designed for 60 different positions. There are actually only 10 different positions the discs can assume, which is a good thing when you think about having to dial in numbers with millimeter accuracy when you’re trying to get into your locker.

So alright, how do we find these 10 positions? It doesn’t require any high-tech wizardry, all you need to do is pull up on the shackle while turning the dial. The dial will only move between a few numbers, and this is the key to finding the combination.

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

Now you’ll be able to see the 10 positions behind the dial, and you’ll be able to find the 10 numbers the combination is picked from. Say you find that the dial sticks between 1 and 4. This is the first position of this lock, so take a number in the middle, let’s say 2. The next sticking point will be between 7 and 10. There will always be a two number buffer between the sticking points, representing the gap between indentations in each internal disc. The indentations are always 4 numbers wide, which makes it easy for us to figure out the rest of our combination numbers – just keep adding 6 to your first number.

So for this lock we have 2, 8, 14, 20, 26, 32, 38, 44, 50, and 56 for our possible combination numbers. Each lock will have different sticking zones so the numbers will vary, but there is always a 6 point spread between them. Hmm, this is starting to look possible!

Okay now we have 10 x 10 x 10, or 1000 possible combinations. Well you could sit down and run through 1000 combinations, mind numbing as that would be, but luckily it gets easier.

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. This knocks our possible combinations down 90 percent. So really there are only 100 possibilities.

But in reality there aren’t even that many. For almost all Dudley locks out there, the second combination number is lower than the first. This may not hold true for all locks, but it’s been that way for every Dudley lock that I’ve seen. This means that our possibilities are reduced to 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1. Which leaves us with a grand total of 45 combinations! The list is so small you can easily write it out.

These are the possible combinations of this particular lock, listing the first two numbers only. For the third number just spin through the sticking zones while pulling up on the lock until it clicks open.

8-2, 14-2, 20-2, 26-2, 32-2, 38-2, 44-2, 50-2, 56-2

14-8, 20-8, 26-8, 32-8, 38-8, 44-8, 50-8, 56-8

20-14, 26-14, 32-14, 38-14, 44-14, 50-14, 56-14

26-20, 32-20, 38-20, 44-20, 50-20, 56-20

32-26, 38-26, 44-26, 50-26, 56-26

38-32, 44-32, 50-32, 56-32

44-38, 50-38, 56-38

50-44, 56-44


I’ve followed this method for a few Dudley locks, and it’s taken me as little as 7 minutes to figure out the combination. Not really that secure is it? It’s a little scary when you think about the thousands of schools, universities, gyms, and other public places where combination locks are supposed to secure your personal stuff. With a little practice, it isn’t hard to imagine anyone being able to open your lock in 10 minutes when there are only 45 combinations to work through.

Say it takes you 30 seconds to find a sticking zone, count up the 10 possible numbers, and write them down. You don’t need to write down all the possible combinations, just start from the first number, keep the second number lower, and head clockwise. If you’re quick about it and can test one combination every 12 seconds (with a spin at the end), worst case scenario it will take around 10 minutes to crack that lock (12 x 45, + 30 seconds = 9 1/2 minutes). And even if you’re not that fast, the chances are only 1 in 45 locks you’ll need to test every possible combination.

Of course, this can also be useful for completely legitimate purposes, like finding a combination you’ve forgotten or removing an abandoned lock without bolt cutters. All padlock-style combination locks are designed pretty much the same, so even if it’s not a Dudley the method above should still be of some use.

**Take a look through the comments for updated info. Also, feel free to post your success stories with your lock letter and whether your first combination number was higher or lower than your second.**

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