Found in 2 comments on Hacker News
blasdel · 2024-01-16 · Original thread
Read the book first, in 2010 a UK man built one from scratch as best he could

http://www.thetoasterproject.org/page2.htm

https://www.amazon.com/gp/product/1568989970/

The Toaster Project is a good example of this:

https://www.youtube.com/watch?v=5ODzO7Lz_pw

https://www.amazon.com/Toaster-Project-Attempt-Electric-Appl...

He attempted to build the basic components of a toaster from scratch. Smelting metal, molding plastic, etc. The book is a tough recommendation because he sortof gives up on the later parts and limps to a finish, but overall its a fascinating look at how difficult these processes are if you build them up from scratch.