This year we had a class teaching basic machining practices in metal work. As a class project we decided to build a steam engine. Considering our knowledge of steam engines to be near zero, we purchased a kit that came with the rough castings and raw materials along with blueprints necessary for a ¼ horsepower scale steam engine.
It quickly became apparent that this kit would be a challenging proposition. Tolerances had to be held very close. The odd shapes of the cast iron castings required some ingenuity just to hold them for machining. Overall it was quite a learning experience for my students and me!
Time constraints didn’t allow us to build a steam boiler to power our engine so we are currently running it on an air compressor. When we first started the engine it required about 65 pounds per square inch of pressure and had to be run at over 100 revolutions per minute. We ran it periodically during the Thanksgiving Fair weekend and now have about four to five hours of run time. During this break in period, parts wear in to fit each other, polishing the mating surfaces. Plenty of lubrication helps this process result in a smooth running piece of equipment. The engine is running much more smoothly now, requires only about 20 pounds of air pressure and will run quite slowly.
The exposed crankshaft, cross-head and valve train make it rather fascinating to watch. We plan to have it running in the blacksmith shop this next week end if you are interested in seeing one up close.