After years of searching I had the money in pocket at the right time.
The Modern Gunsmith: A Guide for the Amateur and Professional Gunsmith in the Design and Construction of Firearms, with Practical Suggestions for All Who Like Guns by James Virgil Howe. As a plus it came with the original slipcase and is inscribed by the author dated 1934. $55 well spent. I’ve had the set in eformat for years but nothing, IMNSHO, matches having the physical media. (My apologies for the crappy picture. My photog-fu isn’t very good.)