It's all explained in the Cooper knife book. Authored by William Martin and Paul Basch.
John Nelson Cooper used the stock removal method to make his knives. He used 01 carbon steel and cartage brass for his guards and butt caps. His handles were made from micarta, he also held two pattens for the way he attached his guard to the blade. The book that was written by Martin and Basch is the only book written and only 500 books were printed, so good luck on finding one. If any one needs more information about Mr. Cooper email me at email@example.com