This interesting little engine, made by Tony Wright, probably to his own design, he calls a Dairy Engine. It is a small portable engine, presumably of a type used on dairy farms.
The 4 wheel unpowered chassis is mild steel (I will probably paint it at some time). The front wheels are steerable and fitted with an A frame for towing. Mounted on the chassis are the vertical boiler and the engine frame. The simple vertical boiler is copper, 54mm diameter x approx 60mm high. It has a single flue and a safety valve. There is no water level indication, superheat or regulator. It is fired by a simple solid fuel tablet tray and is hard soldered.
Steam is fed directly to the back of the engine port face, which is fixed to a bent steel frame. The cylinder is a single acting oscillating cylinder, 7.5mm bore x 17mm stroke, connected to a disk crank. The crankshaft is mounted in brass bearings in the frame. On the other end of the crankshaft is a 31mm diameter solid brass flywheel. Exhaust is fed into the base of the chimney.
The engine was received new having been made to order. The steel chassis is already showing signs of surface rust so I shall probably paint it at some time.