You can think of it as something akin to an adult Erector set. There are brackets and special nuts and a variety of accessories. However, what you do need is a lot of special parts. In some cases, you may want to tap some holes - either that already exist or those you freshly drilled. In general, all you need is a way to cut the extrusion square (or, buy it in the lengths you want) and a way to drill holes in the relatively soft aluminum. But having stock inexpensive aluminum is both strong and convenient. After all, it isn’t hard to build a box out of wood or even aluminum stock. If you are handy enough, of course, you can build all of those things without resorting to aluminum extrusion. Why Extrusions? Hackaday’s own Roger Cheng shows the versatility of aluminum extrusion and shares a wealth of tips he developed for his Sawppy the Rover project. If you need a custom workbench, a light fixture, or even a picture frame, you can build anything you like using extrusions.

There seems to be a lot of people using them, for example, to build custom fixtures inside vans.

But you can use it anywhere you need a sturdy and versatile frame. We use extrusions to create frames for 3D printers, laser cutters, and CNC machines. Oddly, there doesn’t seem to be an official standard, but it is so common that there’s usually not much variation between different vendors. Of course, aluminum extrusions aren’t made from modeling clay, but usually 6105-T5 aluminum. You push some material out through a die to make a shape. If you ever had a Play-Doh Fun Factory as a kid, then you know about extrusions. However, it is one thing to assemble a kit with some extrusions and another thing to design your own creations with the material. T-slot extrusions used to be somewhat mysterious, but today they are quite common thanks to their use in many 3D printers.

Cad extrude rounds corners