Intro: Lockable Wrist Straps
These versatile and sturdy wrist straps are made from materials you can find in just about any hardware store.
Step 1: Materials and Tools
You will need:
* Webbed tie-down straps
* U-bolts (2)
* Flat cable tensioners (2)
* Needle and sturdy thread (waxed thread or artificial sinew works well)
* Soldering iron
* Wide-nosed pliers
* Sharpie or paint marker
A pair of vice grips may also be useful.
Step 2: Measure the Band
Wrap the webbing around your wrist, leaving a few centimeters of "tail" to one side. This tail is the short end, the other side is the long end.
With the Sharpie or paint pen, mark the center of your wrist with an "X", on the part of the webbing closer to the long end.
Step 3: Prepare the Cable Tensioners and U-bolts
The cable tensioners come with bolts, which may be spot-welded into place. You don't need the bolts. If the bolts are spot-welded in, you can break them free with a pair of pliers. (Remove the nuts and washer from the cable tensioner first.)
To do this, place the cable tensioner in the jaws of the pliers with the bolt end against one side and the body of the cable tensioner against the other. Squeeze the pliers until the weld gives way, then remove the bolt. You may need to wiggle it free with the pliers.
Next, make sure that the U-bolt fits in the holes of the cable tensioner. You may need to spread or squeeze the legs of the bolt a little in order to get a clean fit. The U-bolts in these pictures needed to be widened a little; I used the rounded back of my vice grips as a curved jig and used the vice grips and the pliers to wedge the legs open.
Step 4: Make Holes
Line one of the U-bolts up so that the X is directly between the two legs of the bolt, then place a dot at the end of each leg, centered width-wise on the strap.
Heat up your soldering iron, then push the tip through the strap at each dot. This melts the plastic and creates a clean hole.
Step 5: Assemble the Hasp
Insert the legs of the U-bolt into the holes you made. The hasp pokes out on the right side, it'll be secured on the wrong side.
Slip the cable tensioner onto the wrong side of the strap, with the flat face against the webbing. Put the washer on, then screw the nuts onto each end of the U-bolt so that the nuts are flush with the bolt ends. This prevents the bolt ends from sticking out and causing injury or wearing through the webbing.
Step 6: Finish the Hasp
Fold the long end of the strap over the cable tensioner, so that the entire tensioner is wrapped in a loop of webbing.
Using a strong stitch such as the backstitch, sew straight across the two layers of webbing, trapping the hasp in place. Sew down the edge, at least as far as the webbing is wide, then back across and back up, forming a rectangle. Sew a diagonal across the rectangle. (You may want to do this along both diagonals.)
Cut the long end of the webbing just below the lower row of stitching. Leave a little room in case it ravels.
Next, sew up the sides of the loop around the tensioner so that its entire surface is covered. If your webbing is wide enough, sew it flat using the backstitch. If it isn't (as in these pictures), use the whip stitch.
Step 7: Mark and Cut the Closure
Wrap the strap around your wrist such that it isn't too tight (when it's closed, you should be able to get two fingers between the strap and your wrist) and the tail hangs off to one side. Have a friend or a tool help you keep the strap from flopping open while you mark it.
Draw a line as long as the distance between the hasp legs on the free end of the strap.
Take the strap off your wrist, and with the soldering iron, melt the webbing along the line you drew. You may need to trim bits of molten plastic from the edges of the hole; it comes away easily with scissors.
Now you can try it on! If you need to, you can lengthen the closure on either end using the soldering iron.
And you're done! Use a carabiner, locking bolt, crab-claw clip, padlock, or your other favorite implement to secure the strap in place.