Whether it’s wood, metal, plastic, or otherwise, when it comes to obtaining materials for your builds, you have two choices: buy new stock, or scrounge what you can. Fresh virgin materials are often easier to work with, but it’s satisfying to get useful stock from unexpected sources. This CNC router for PVC pipe is a great example of harvesting materials from an unusual source. [Christophe Machet] undertook his “Pipeline Project” specifically to explore what can be made from large-diameter PVC pipe, of the type commonly used for sewers and other drains. It’s basically a standard – albeit large-format – three-axis CNC router with one axis wrapped into a cylinder. The pipe is slipped around a sacrificial mandrel and loaded into the machine, where it rotates under what looks like a piece of truss from an antenna tower. The spindle seems a bit small, but it obviously gets the job done; luckily the truss has the strength and stiffness to carry a much bigger spindle if that becomes necessary in the future. The video below shows the machine carving up parts for some lovely chairs. [Christophe] tells us that some manual post-forming with a heat gun is required for features like the arms...