This series of books is an excellent guide for making the tools needed to do precision metal work. Starting from nothing the whole series bootstraps its way up from hand tools to a metalworking lathe. Fundamental to the process is sand casting parts in aluminium scrap.
I have read this series cover to cover a number of times and while it is highly unlikely I will ever do this in practice, the books were both fascinating and enjoyable. The process is very time consuming - each part is essentially hand-crafted - but definitely achievable by anyone with a lot of patience and a modicum of skill with hand tools. A lot of what is covered would transfer really well to making other projects using the same fundamental techniques.