I was inspired by zignig's Printable Desk Clamp http://www.thingiverse.com/thing:683 . I used hex nuts instead of square nuts because hex nuts are more common. All the parts are easily available at hardware stores and hobby shops. The total cost is about $4.50 for this clamp compared to $50 ones. It is used for holding circuit boards at comfortable angles, hobby modeling, and holding stuff. Enjoy.The picture of all parts does not show two nuts that I had already hammered in but I did not want to take them out. Also it does not show 20mm brass tubing as I already hammered some of them in.Nuts and Bolts1/4-20 Bolt 2in long 1/4 Wing NutRods and Tube 130mm, 120mm, 80mm, 50mm of #10-24 threaded rod 120mm x 2 Square brass tubing 3.2 mm outer diamter. Rails 20mm x 6 Square brass tubing 3.9 mm outer diamter. Guides (Test the tubes at the store. The smaller tube should slide easily and snugly into the larger tube.)Cut six larger diameter pieces 20mm long that would serve as guide for the rail which is the smaller diameter brass tube. Then tap then in into the stopper and hands with hammer.Also, if the threaded rod is difficult to insert into the the plastic parts then you can drill them with a 6mm or 3/16in drill bit.