Courtesy of
Model Components (Aust)

The GAGE HM1 steam engine kit is a double-acting, single cylinder, non-reversing steam engine. The HM1 is constructed from aluminium, brass and steel. The kit contains a detailed instruction manual, all parts fully machined and all necessary hardware, including brass hex-head bolts for all visible hardware. A "spin-tight" wrench is also included to install the brass hex-head screws.
This engine will operate from 5 to 35 psi steam or air pressure. This engine can be easily powered by one of our 2" Colonial style boilers.
Bore = .344" (8.74mm) Stroke = .500" (12.7mm) Shaft diameter = .125" (3.2mm)