When working with my first prototype robot limb, I decided to make it from plastic tubing. This decision was made mostly because of cost since plastic tubing is very cheap. Another aspect was availability and space. It became clear after creating this first prototype that I would need other materials to construct my prototypes from.
Right now I don't have space in my apartment for many tools I am looking to buy a house soon, and hopefully it will have plenty of room for my workshop in the basement.
Looking farther into the future, a lot of the parts for the robot will inevitably be machined from metal, and that requires me to get hold of a mill and other metal working tools. Since a CNC mill is really expensive, and since it is basicallt just a robot with 3 actuators (or 4 if you get fancy) I have therefore decided to create my own CNC mill as part of this project.
Since the creation of this CNC mill is not the primary goal of the project, I have decided to cut many corners to speed up its construction. I have cheated and bought a book on the subject. Basically the book is a guide written by someone like me who would like to make their own CNC.
I will take its advice, and use parts from the book directly, but change some things to better suit my own needs.