I went ahead and took a scan of one of my straps. This one doesn't have any metal hardware on it.
Here is a picture of the assembled strap. Very crappy res, but you get the just of it.
Here is a close up scan of the disassembled parts:
The skinny piece then weaves through the big piece like so:
..And back through itself like this:
It's quite a simple way to make solid, adjustable straps. Viva la friction!
Here is a pattern I made, which has contours to make the strap flow better. One can see how that would be helpful with heavy/rigid material. This is only the fat part of the strap, of course, but Im sure you can see how it correlates with the previous images and adapt it to your own uses. Im around 5'10 and 150lbs, and that particular contour works well for me. The image is fit to print out on a legal size sheet of paper. Just set the page size to 8x14, and the page margins as small as you can in your image software when you print it out.
