Stan Bray's "Simple Sam"

After getting Elizabeth chuffing happily on the bench, and the heroes engine spinning away, I wanted something simple to build confidence before tackling anything more complicated.

Enter Simple Sam from Stan Bray's Making Simple Model Steam Engines.

If Tubal Cain's Elizabeth is "simple but proper", Simple Sam is... well... gloriously basic. It's a single-acting oscillator that looks more like a clever desk toy than a "real" steam engine. No slide valve, no eccentric, minimal parts — yet it runs really well! Stan Bray designed it as an entry-level project using bar stock on a small lathe and mill (or even hand tools for some bits), perfect for anyone still getting comfortable with their workshop.

Building Simple Sam

Key parts:

  • Cylinder - 15/32" brass round, with a 3/8" bore, drilled then reamed to size.
  • Port Face - 1/2" x 5/32" brass rectangle
  • Cylinder Cover - 1/2" brass round, turned to 1/8". 1/16" at 3/8" to fit cylinder.
  • Pivot Pin - 3/32" stainless steel rod, threaded 7 BA at each end.
  • Frame - Brass rectangle, 5/32" x 2 11/32" x 3/16" for the upright, soldered to a base piece which is 5/8" long.
  • Crank - Crankpin & Crankshaft fabricated from mild steel
  • Flywheel - turned from 1" brass round, 1/2" wide with 6 BA tapped hole for grubscrew.
  • Piston, Connecting Rod & Big End - a piece of 3/8" brass rod, 1 3/8" long.

Photos from the Workbench

Completed Engine

simplesam.jpg

Next Up

If Simple Sam behaves, it'll be a nice confidence booster before I tackle my next project.

Next engine: a brass wobbler!

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