Clamps - How do they do it?

[Ferdi Willemse]

I'm going to make a new DIY shoulder mount which uses two 15mm rods.
This time I also want to experiment with the clamps you find on so many support systems. Now I personally don't own a pre-made support system, so I can't see what these clamps are made of.

Can someone share me their thoughts on how they are made? In particular the materials used and the diameter (probably a little smaller than 15mm?)

This is the kind of clamp I'm talking about (bottom part):

http://www.zacuto.com/z-round_mount_on_mini-mountlg.jpg

[twocik23]

These clamps are CNC'd and made are of 6 series or 7 series aluminum, then anodized black and red.