Bumpkeys: A Real Threat?

Bumpkeys or bumping a lock are very rarely used in crime and most information about them is alarmist in nature. That being said, they represent a well-known vulnerability in pin tumbler locks all around us (search for bumpkeys on youtube and see, they are widely used and discussed by hobbyists) and people who have seen them demonstrated usually want locks that defend against bumping because it appears to be so easy to do, and most people want it to be hard to unlock their door without a key!

Upgrading to locks that can’t be bumped is not terribly expensive. I made this video to show to people who are curious about how bumpkeys are used because people ask me frequently due to a trend several years ago on televised news channels talking about the danger.
This is a real storefront door in Seattle that criminals bypassed. The property owner asked me to improve his security. First, I recommended the door installer come back and fix some things. Second, I gave him the option of buying higher security lock cylinders. He asked me to demonstrate where his current lock cylinders were lacking, and I tried a bumpkey on his lock. I was surprised how fast it opened, usually it takes at least a few taps.
The cylinder that came with his door didn’t have a protection ring to guard against pipe wrench attacks, it was made of pot metal that deforms easily, and the tolerances are low in such lock cylinders making the lock easy to pick or bump (though the likelihood of a criminal using such techniques is very low compared to the chances of a rock or butter knife or screwdriver being used). He opted for a cylinder with a protected keyway, security pins and a hardened steel ring. The door company quickly  fixed their errors when they were pointed out and now the customer has a much more secure facility.

The cheapest way to prevent bumpkeys from working in your door is to simply use a lock that has a keyway other than Schlage C (SC1) or Kwikset’s KW1. There are hundreds of keyways that are readily available but most people on the internet are talking about bumpkeys in the previously mentioned keyways of SC1 or KW1. If you have an L4 lock cylinder for example, neither of these common keyways would work. Of course, somebody could still make a bumpkey out of an L4 blank but then it would be a targeted attack instead of a burglar picking the low-hanging fruit.

It can be expensive to replace all of your keys and lock cylinders but it isn’t very expensive to put security pins in your locks when you have them rekeyed.  Most locksmiths will only charge a dollar or two extra per lock for this. I have kits for retrofitting most lock cylinders with security pins and much stronger springs that make bumping nearly impossible in a conventional pin tumbler lock.

The best way to prevent unauthorized access is to make it much harder for the bad guy to get a key to make a bumpkey out of, or use a lock that doesn’t work with bumpkeys. Give me a call if you are concerned about your property’s security. I can give you options for different ways to improve your property’s defenses.

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Bjørn Madsen

I am the Seattle locksmith you've been looking for. High Quality work at a reasonable price delivered in a timely fashion.