http://www.lockpicks.com/index.asp?Page ... &ProdID=56
Materials:
1.) You will need about 20 cm’s of a nice stiff wire. I’m not sure what gauge or type of wire I used, but if you head to a Wal Mart, a craft store, or any hardware store there should be plenty of wire to choose from.
2.) One barrel nut. A barrel nut is a regular hex nut, but made much longer. It is sometimes used to connect two threaded pieces of metal together. Again you can find this at any hardware store.
3.) One bolt that will match your barrel nut.
4.) A drill. Preferably a drill press, but I suppose you could use a power drill if you’re careful.
5.) A vice.
6.) A pliers.
7.) A bench grinder, or files, or a dremel tool.
Procedure:
1.) Determine the length you want your wrench to be. I wanted mine to be 10 cms in length, therefore I cut a piece of wire to 20 cms. Mark the middle of the piece of wire with a pen and bend the wire into a “V” shape. Use a pliers or vice to try and pinch the folded center as tight as possible.
2.) Using your drill, drill 2 holes straight through the barrel nut. The spacing doesn’t have to be precise, the important part is that the holes are in a plane next to each other and not “off kilter.” You’re going to be feeding the wire through the barrel nut so try to make the holes just big enough so that the wire fits through the nut snuggly. (see picture below for a rough idea on spacing.)
3.) Feed the wire “V” through barrel nut.
4.) Using files, a dremel tool, or a bench grinder, grind the tips of the “V” wire so that they’re squared off slightly. This is to make sure the wrench will fit into a lock and won’t slide around once inside of it. While grinding mine I had a spare lock with me so I could match the wire up next to it to make sure I hadn’t made it too thick or thin.
5.) Bend the tips of your wire to the desired “tensioning” angle.
6.) Screw in your bolt, cut the bolt to length if necessary if a lot is sticking out (which was the case with mine.)
Notes:
Play with the angle of the “V” a little bit before you feed it through your barrel nut. You want the barrel nut to be able to slide up and down the wire changing the angle of the wire slightly as you do so.
It might also be a good idea to create a handle for your tension wrench. Be creative, electrical tape, duct tape, rubber dipped handles, etc.
Operation:
Hold the wrench up to the lock you wish to work on, insert it into the lock and adjust the barrel nut until the angle of the wire is at the right distance, not too wide or narrow for the keyway. Lock the wrench into place by tightening the bolt on the barrel nut.
.... I´m gonna have to do some serious search function searching 
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