I picked up a copy of "Making Simple Model Steam Engines" by Stan Bray and had a look at the various models he offers in the book. Each model has a complete plan and description of the build. Since I am catching the steam engine bug I am determined to learn more about these little engines. As a first exercise I thought that I would make up a parts file in CAD for one of the designs in the book and try printing it out on my spiffy new 3D printer. That would give me some CAD and 3D printing exercise and a good look at the parts for a simple oscillator. Just for fun I entered 1.25 in the scale window and voila! A larger engine. I modified the frame for a more solid unit and printed it out too. I used brass tubing for the intake and outlet ports and drill rod for the crankshaft and crank. Hex head screws and springs form ballpoint pens as well. The rest is all printed.
The little guy turned out really well and I am going to see if it will turn a few rpm with air pressure. I suspect I will have to make up a metal flywheel to actually get it to run. The big one has too much slop in the piston and won't line up the ports with the cylinder. But all the relationships with the crank throw and the alignment of the ports with the intake of the cylinder came out just right. Good lesson on how critical these measurements are. And the resulting engines are just so darned cute! Now to metalize them and try my hand at making boilers. Silver soldering is not my strong suit but lots of practice should help.
The little guy turned out really well and I am going to see if it will turn a few rpm with air pressure. I suspect I will have to make up a metal flywheel to actually get it to run. The big one has too much slop in the piston and won't line up the ports with the cylinder. But all the relationships with the crank throw and the alignment of the ports with the intake of the cylinder came out just right. Good lesson on how critical these measurements are. And the resulting engines are just so darned cute! Now to metalize them and try my hand at making boilers. Silver soldering is not my strong suit but lots of practice should help.
