Pipe Clamps

These are meant for building structures from pipes; furniture, railing, etc. Designed as a cheaper alternative to the metal clamps and fittings made by companies like Kee Klamp and Alvin Industrial.

Here are some things made with pipe clamps:
http://www.simplifiedbuilding.com/projects/photos/

Disclaimer:
I have no affiliation with the aforementioned companies. I take no responsibility for what you do with the files I have provided.