Enhancing Deadbolt Security

Enhancing Deadbolt Security

In my last post I recommended some specific locks. This week’s post will cover improving the security of existing locks, or the Grade 1 hardware I recommended. The goal is to create a “Grade 1+” lock, by adding some additional security measures. Enhancing deadbolt security very achievable with just a little spare time, access to a locksmith, and some basic hand tools.

Deadbolt Installation and Adjustment

Ensuring your deadbolt is correclty installed and adjusted is the most important step you can take toward enhancing deadbolt security. Modern deadbolts are designed to extend 1″ from the rim (edge) of the door. You should ensure that your deadbolt extends fully. If it is only partially extended it is not truly “dead”, meaning it can be pushed back into the door. Only when fully extended is it locked into place. Using a metal strike-box like this one can help you ensure the deadbolt extends fully.  The strikebox will also offer much greater kick-in protection than a standard strike plate.  It should be secured with 3″, coarsely threaded wood scews. The image below shows a steel strike box (left) and a simple strike plate. The strike plate is much more common and provides precious little security. It is typically attached with very short screws to a pin or composite door jamb.

Enhancing Deadbolt Security

To verify that your deadbolt extends fully, open the door and extend it.  Using a Sharpie, draw a line on the bolt, as close to the edge of the door as possible.  Retract the deadbolt and close the door.  With the door closed, extend the deadbolt. If the line you drew is not visible, the bolt is not being allow to extend fully. You should correct this situation immediately; otherwise your deadbolt is not provide the full measure of protection it should.

Pinning Configuration

This section and the section on security pins requires working knowledge of how the pin tumbler lock mechanism functions. Watch this video for a quick tutorial on pin tumbler locks.  This video further explains how to disassemble a pin tumbler lock.

If your lock is milled to accept six pins you should install the sixth pin. This is probably the single biggest step you can take for enhancing deadbolt security against covert entry techniques.  While most Grade 1 deadbolts are milled to accept six pins, they are frequently shipped with only five installed. To find out for sure if yours will take six pins (if it does not already) you will have to disassemble it. You will then have to install a bottom/key pin, a top/driver pin, and a spring. You will also have to have a new key cut on blank that is long enough to accept six pins.

Have your locked pinned with good combination of long and short pins.  Schlage’s keying specifications offer 10 different depths for each cut position on the key, “0” being the shallowest, “9” being the deepest.  The ideal key would have no two cuts of the same depth, and a good range of cut depths. Bad example:  42345.  The variation is really only four cut depths (2-5).  This lack of variation in pin length makes the lock much more easily picked/raked, or bumped.

A much better example would be 92170.  The varation here is 10 (0-9), and there are a couple of other things going on.  A deep cut/long pin up front (the 9) means anyone picking the lock will have to pick around this pin.  It also means if anyone tries to impression your lock with a key blank, it will probably break before they are finished because they are removing so much material at a critical portion of the blank.  A very short pin in the back of the lock (the 0) is really hard to reach with a pick without touching (and potentially disrupting) other, already-picked pins in the lock.

Enhancing Deadbolt Security
This pinning configuration isn’t bad at all. Note the code stamped on the bow of the key. This is the lock’s pinning or “bitting” code, and having it stamped on the key is not a best practice.

Getting a specific pinning configuration will require a trip to the locksmith unless you own a the appropriate tools and a pinning kit. Pinning kits for Schlage and Kwikset locks are available online, and are almost certainly cheaper than having a locksmith rekey your locks. You will still have to visit your locksmith to have keys cut, however.

Security Pins

Security pins are specially-shaped driver pins. There are several varations of security pins including spool pins, serrated pins, and mushroom pins, each so named because of its shape. Regardless of which type you use, all make your lock more secure against lockpicking. It is rare that these are installed from the factory. A locksmith can install them for you, or you can install them yourself. The top pins in locks are nearly universal, so a generic set of security pins like this one should work in most common locks.

Threat Model Based Deadbolt Selection

If anyone is seriously interested in security pins, contact me. No promises, but I can probably send some out.

Balanced Pin Stacks: You can also make your lock more difficult to attack by using balanced pin stacks (a “pin stack” is the combination of a bottom pin, top pin, and spring). Each pin stack should have the same total length as all others in the lock.  This is accomplished by using top pins of varying lengths: longer top pins coupled with shorter bottom pins, and vice-versa.  This creates a uniform pin stack height and provides protection against certain kinds of attacks. It may not always be possible to completely balance pin stacks due to space limitations in the lock.  Pinning specifications for Schlage offer three top pin lengths (.235”, .200”, and .165”).  These lengths can be supplemented with intermediate lengths, but you should not exceed the maximum length (.235”) as anything longer than this may cause problems in the lock by over-compressing its spring.

Enhancing Deadbolt Security
A balanced pin stack with an assortment of security pins.

Keyways

This one is only applicable if you’re shopping around for a new lock and have some serious patience.  Lock manufacturers offer a number of different keyways (shape of the keyhole).  However each manufacturer only markets one or two the residential sector.  Schlage, for example, uses it’s “C” keyway in almost all of its residential hardware.  Find a friend with an OEM Schlage key and I’d bet it is marked with either a small “C” or (less likely) “E”.  As a result bump keys for these keyways are commonly sold, as are key blanks. If you can find a lock with a non-flagship keyway you can make it more difficult for some one to generate a copy of your key because acquiring key blanks is much harder. The downside is that finding a lock with a non-flagship keyway can be challenging. Usually these keyways are reserved for very expensive commercial hardware. Your best bet is to visit a locksmith and ask for one.

Door and Hinges

Reinforcing your door is a good step to take, regardless of which locks you choose. Even an Abloy will do you little good if your door delaminates or falls off the hinges. There are several products on the market that improve the rigidity of the door, the jamb, or both. These include simple reinforcement sleeves that slide over the door and are held in place by the locks. More comprehensive products that also reinforce the door and the jamb are available, including the Door Devil and DJArmor line of products.

It is also a good idea to reinforce the hinge-side of the door. This is especially true if your door opens outward, because your hinges are on the exterior of the door. If you are using standard residential hinges, the pin holding them together can sometimes be tapped out, and the door lifted out of the frame.  Hinge security pins like these “security hinge bolts” or the “HingeMate” can prevent this from happening, and installation is very simple.  You should also ensure the screws holding your door to the frame are contacting a stud. I recommend replacing standard-length screws with 2 1/2″ or 3″ wood screws.

Conclusion

Enhancing deadbolt security – and the security of your doors and hinges – can allow you to make a major security improvement with little expense. It is also (for me at least) a tangible, phsyical way to interact with my own security. I hope you got something out of this post. If so stay tuned for more physical security content, and for the upcoming Complete Privacy and Security Desk Reference, Volume II: Physical.

 

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3 thoughts on “Enhancing Deadbolt Security”

  1. My deadbolt only has a strike plate, so that’s something I need to remedy soon. Having a deadbolt is a great way to increase security in general. Back when deadbolts were scarce, people were able to get into a door with a credit card. The harder it is to get into a house, the more likely a burglar is to give up and try another place.

  2. Do you recommend also replacing the screws holding the hinge to the door with 3″? Is there any risk of the door splitting?

    1. Dave,
      It depends on the door. If it is light residential metal-wrapped door there isn’t much chance of screws splitting it; on the other hand that type of door probably isn’t going to survive a kick-in anyway but I would upgrade those screws to 2″ to make it as strong as possible. If it’s a solid wood door the possibility of splitting is there. I would drill some pilot holes and maybe go 2″ or 2 1/2″.
      Justin

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