Panzer tank hull being quenched

[Toolmaker51]

I save a lot of these unique photos of manufacturing processes especially the ones from an eara when it would have been thought impossible to accomplish.

Frank, I agree wholeheartedly. My favorites are the WWII era ads from Fortune and Life magazines, featuring American manufacturing supporting the war effort.
In my own short life I recall when impossible was just a term, the perspective was difficult or a challenge. Intuition, judgement of options, testing, and adding 10% margins solved many projects.
Impossible to accomplish wasn't known until professional engineers and digital designwork collided with centuries of fit, form, and function, initiated by sliderules and notepads.
Egyptian Pyramids. Hoover Dam. Small Block Chevy. Tennessee Valley Authority. Model T. Wright Brothers Flyer. Golden Gate Bridge (nearly any bridge for that matter, including Iron Bridge in England...) Aircraft and radial engines built before the 60's. V Twin Harley-Davidson's...need I continue?
Some not so successful, because 'certified' engineers & accountants got into the act of design; The Titanic, Galaxy Note 7, (google 'design failures for plenty more). The Titanic is rather unfairly judged, unsealed compartmentalization notwithstanding. The failure is not of the ship so much, as the rhumbline courses it was ill designed for.