Daryll Smith is a Principal Designer and Instructor at the Medtronic Tempe Campus. He used his Cube 3D printer to create a fully-working oscillating steam engine to share with his students. Daryll was gracious enough to share his story with us.
I grew up the son of a backyard inventor and hobbyist. At an early age I learned about woodworking, metalworking, and mechanics – aviation and automotive. I now have a career as a Tool Designer and Evening Adjunct Instructor, for a local Community College, where I share my knowledge and practical experience. I have been interested in 3D Printers since the 1990’s although their price range was certainly outside that of a Hobbyist. Today we have DIY Printers and commercial Printers that make owning and operating a 3D Printer very affordable.
I purchased a 3D Systems Cube printer to explore, and print, some of the mechanical interests that I’ve long to make but didn’t have the machine shop or money to pursue. One of these interests was a simple Stream Engine. Before going out and designing one from scratch I did a search and found a YouTube video showing an Oscillating Steam Engine, by Charles Babbage, which lead me to downloading his files and printing my own engine. Point of interest: The Oscillating Steam Engine, also known as a Wobbler Steam Engine, is usually one of the first projects a novice machinist will make.
To make the engine work cleanly, I sanded the surface between the cylinder and upper frame with 400 or 600 grit sandpaper to achieve a smooth surface between the two mating parts (to provide a better seal and reduce the loss of air pressure). It is also important to lubricate the moving components. I recommend and used a dry graphite lubricant (like Hob-E-Lube – left over from my son’s Pinewood Derby days) on the moving parts and had instant success! (Notice the graphite on the piston, crankshaft pin, and between the cylinder and upper frame. The crankshaft and bushings need some too)
This engine runs on air pressure (since actual steam would soften the plastic) which can be supplied by canned air, like that used to clean your computer or power an airbrush, or an air compressor with a regulator to decrease the pressure down to a range of 5 to 20 PSI. (I used a can of airbrush propellant) The flywheel has spaces for the insertion of coins to add weight and aid in a smooth running engine. This is more noticeable if you try to run the engine at a very slow speed – lower air pressure.
I plan on using my engine in my college classroom as a project for the students to design and detail along with showing them a working model of the project. My future projects include designing and building a multi-cylinder Wobbler Steam Engine, a “steampunk” bicycle with a planetary gear-driven front wheel, and a 1/25 scale Teardrop Camper Trailer for my model railroad.
I recommend printing and building a project like this one to spark your mechanical imagination and explore the limitless boundaries of 3D printing.