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Lock Bumping Techniques

Posted by Mark Stuckey on

To successfully bump locks you need a lot of practice, the right tools and the right frame of mind. We'll provide the right tools and we can even help with the frame of mind, but practising is pretty much down to you.

Here's a round-up of advice, diagrams and tips for the most FAQ's concerning the bumping technique. Bumping a lock is quite an unnatural set of movements that happen in both series and parallel. The principles of bumping are simple, learning it takes minutes, working it takes a little longer and then it's up to you, how good do you want to get?

Before you start, setting the key -

Putting a bump key all the way into a lock as you would a standard key is no good. The 'peaks' on a bump key need to sit in front of each pin. Our keys work on both 5 and 6 pin locks and you need to know how to set both. Here's a diagram to explain this.

Key Positioning

Key Positioning Here's a diagram of basic terminology:

Bump Key Glossary Valley Peaks

As you can see, to bump a six pin lock we use the ground down shoulder of the key as the 'first' peak. You can actually do either for 5 pin locks – it doesn't matter – in fact it's often worth trying both with a five pin lock just in case. There's more to setting the key than just where the pins sit.


Below is the entire list of different variables, choices and options you must exploit in many and different combinations until you get the right one to open the lock.

Keys Laid out
    1. How are you setting the key? Is it 5 or 6 pin? Do you want to push it left, right up or down in the lock before you start? These different positions will cause different responses in the lock so make sure you try them all. Are you using springs or dampeners? What pattern and/or depth key are you using? How have others responded so far?
    2. How are you applying turning pressure? When the pins jump up above the shearline, you need to have some pressure on the key to allow the plug to turn. The 'plug' is the moving part of the lock the key enters and turns. If you're holding the lock in your hand, you can apply pressure using your index finger as it curls round the underside of the cylinder. The tip of your finger gently presses against the underside of the key, pushing it clockwise. Some people prefer to use their thumb whilst holding the lock in the same position. If the lock is in a door, there's more limitations and you have to take these on board. Most people use their index finger on the top, left hand side of the key, pushing it clockwise. You'll have to experiment with all of these to open the most locks. There isn't one way that's right per se, there's one way that's right for the lock you're trying to bump.
      There's two common mistakes with 'turning pressure', the first being too much pressure and the second being increasing the pressure at the last minute. Both of these problems are easily overcome but worth paying attention to early so as to not get into bad habits. The pressure is gentle and overdoing it will only prevent you from bumping the lock. Imagine pushing a dead beetle over a pain of glass, about that light. Obviously you have to vary this, it's another range to exploit, but you'll find it's nearly always a lot less than you think. Increasing pressure at the last minute is avoided simply by relaxing and concentrating. Once you have successfully bumped a few locks, you'll understand this better and it will become second nature. And don;t forget to vary 'where' you're applying the pressure, different stresses will affect the entire process.
    3. Presetting
    4. What are you hitting it with? A dedicated bump-hammer avoids a lot of issues here as they tend to be good for the job. A screwdriver handle is a good second for starters and ever butter knives and light mallets have been used. Find something you're comfortable with, has a good range of swing and feels comfortable in your hand. The 'head' must be heavier than the shaft and the 'face' must reduce 'push' as much as possible, you really want that key to 'ping' off the bump-hammer.
      You don't need to hit the key really hard. Sure, some keys need quite a strike, but on the whole you'll do well just giving it a light tap. You don;t just have to hit it from behind either. If you've seen some of our videos you might have seen me 'Swing & Clip' the key. This technique illustrates nicely how little you need to hit most locks to open them. You swing in an arc and clip the key on the way past. It's the slightest of clips and illustrates nicely how little 'weight' you really need. Remember, you're only moving a few brass pins a few mm.
      From what angle are you going to strike the key? Coming down on the back/top. Middle, bottom? Divide the head of the key up into three and try them all, then vary what horizontal angle you want to come from, left or right. Variety is all you have at your disposal, use it.
    5. Would the lock benefit from dampeners or springs? Most do - not all - but you'll often do well to give it a go if you're not having much success. Don't forget to mix and match your springs and dampeners, mix materials, widths, use a spring and a dampener, then the other way round etc. Some people like to use a tension wrench that they put through the hole in the key head, so they can apply a more sensitive 'turning pressure'.
      Remember, there's loads of options when bumping a lock and if what you're doing isn't working, try something else. Good luck and happy bumping....

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