I first saw these on David Hobby’s Strobist blog in his “On Assignment” section here.  After that I had always been interested in making some myself but never took the time (all of 5 minutes for two).

All you need is a 1/4″ x 20 screw and a couple bolts for each one you’re going to make.  You’ll also need a swivel adapter stud for each clamp you’re planning on making.

Using a hobby knife, cut a small hole on each side where the hole int he handle is  (if you can’t find it, hold the handle up so light is behind it).

Stick the screw through the hole from the inside  and bolt it down.  then screw the swivel adapter stud on, and you’re done!  Easy peasy.

The spring clamps are ~$3 and the screws and bolts are less than $2 for more than you’d ever want to make.