Big Boy Steam Engine

 

This is the largest engine I have built yet and is almost the limit of my equipment based on the flywheel size.

  

 

This is not the fastest engine in my stable, mostly due to a long stroke and heavy flywheel.  The bore and stroke are .75 X 1.0.  It is the most powerful one I have built.  At 20 psi it will only hit about 800-850 RPM, but it is not easily slowed down by rubbing the flywheel.  This was not a kit.  All parts were machined from brass and aluminum stock on hand except for a few steel pins and the mainshaft.  The mainshaft is mounted in oilite bronze bushings pressed into the mount stands.  I expect it to run for a long time.  The base size is 8 X 10 inches.