This paper steam engine is based on Richard Ademek’s CAD drawing of a Riches and Watts nominal 2 ½ horsepower vertical A-frame double acting simple slide-valve steam engine circa 1870-75. The original engine was used to drive a water pump to irrigate the fields of Norfolk. If this model had a scale, it would be roughly 1:19. I had to double the size of the eccentric and strap in order to make it buildable. Everything else is close to scale, but changed in design and apprearance because, well, paper isn’t iron. [via] Link.