2008-07-10

Make your own lock picks - Part 2

Series: Make your own lock picks
Part 1: Grind out a simple lock pick
Part 2: Make a tension wrench
Part 3: Advanced lock pick profiles

In this series, I'll show you how to make a set of high-quality lock picks from stuff you either already have laying around the house, or materials that are easy to acquire for cheap.

In the second part of this series, I will show you how to make a tension wrench. Tension wrenches are usually made of spring steel. They're inserted into the keyway with the lock pick to apply a slight amount of turning force to the lock cylinder. This helps the locksmith feel when the pins hit the shear line, and keeps set pins from falling back down. It's difficult (and silly) to even try picking a cylinder or wafer lock without a separate source of tension, so this should be considered a must-have tool.

Tools and things you will need to follow along doing it my way:

  • Beer (very important, or not. But good to have)
  • A rotary tool such as a Dremel would be helpful
  • Grinding discs for the dremel
  • Two pairs of pliers or adjustable crescent wrenches
  • Diagonal Plier Cutters (Dikes)
  • Eye protection
I've found that it's more trouble than it's worth to make a tension wrench with a hack-saw blade. The tension wrench should be narrow and provide lateral spring.

Making tension wrenches from windshield wiper blades:
I thought I was going to have to go dumpster diving on my way home from work this afternoon to find an old wiper blade in the trash bin behind some car parts store. As luck would have it, I found some old blades in the middle of an industrial park on my way home. They'd been run over and mangled, but that's okay.


Using pliers, remove the blades and the metal rails around them.


Here are the parts we're after. They look a lot like those street sweeper bristles, don't they? You can throw away the rest of the wiper blade and arm assembly.


Using pliers, bend the wiper blade rail as shown. Bent this way, the long part will act as a spring to give us more control over the tension applied to the lock cylinder when we go to use it.


Break out the dikes and cut off the excess length of rail.


One wrench is bent at about 90 degrees. The other one is a bit more obtuse than that. The obtuse angle wrench will come in handy once in a while.


If you wiper blade rails didn't have the narrow spot toward the end like mine did, then treat the wiper rail as a street sweeper bristle.

Making a tension wrench from a street sweeper bristle:

First, using pliers or crescent wrenches introduce a 90 degree twist at the end of the bristle about 3/4" from the end.


Start twisting...


And voila!


Next, gently introduce a light and round bend to the end of the bristle. If you crease too hard, it will crack and you'll need to start over again.


The wrench should now look like this:


We don't really need to polish the tension wrench, as it won't need to glide softly past the pins or tumblers in the lock the way the individual picks do. You may wish to grind any sharp edges off, though:


Here we have the small diamond rake pick and the three different tension wrenches.


Bonus: you can make tension wrenches out of girly things such as hairpins or the underwire out of an old bra.


Series: Make your own lock picks
Part 1: Grind out a simple lock pick
Part 2: Make a tension wrench
Part 3: Advanced lock pick profiles

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