It is always exciting to see builds of our engine plans, this one especially so as it will be the oscillating engine on steam. Up until now I have only run this engine on compressed air. This build is by Michael Prady and this is a great mix of original design, changes in materials and additional design features.
With Michael’s permission I have posted the images and words from our correspondence as I think this just shows a wonderful approach to building this engine.
I originally saw your engine on Pinterest and just followed you from there, my wife bought the pdf drawings from you, but I decided to build a boiler and economise feed pump first, the boiler is hydraulic tested to150psi, so a safe limit of 75 on steam, however I have the safety valve set at 50psi.
I’m putting a superheater in the main steam line as I think it’s too far for wet steam especially as it’s running a displacement lubricator too.
I’ve just modified slightly, as you can see it’s the opposite way round to yours, it should mean it just runs in the opposite direction.
We had a discussion around the piston rings as I show them in the plans, but I have to be honest and say that I never fitted them to my engine…..Michael’s solution to this is rather cool and reminds me of ET Westbury’s approach to piston and liner pairs.
I have honed the cylinder out to 0.5925inch bore, removed the bronze piston and replaced I with a solid cast iron piston of 0.592inch, it is a beautiful fit and both should expand at the same rate, the proof will be in the pudding if it runs.
I have thrown together a little displacement lubricator out of brass tube and scrap ends, it was dead simple and cheap to make.
Manifolds are fitted, she runs very sweet on air, got a beautiful exhaust beat.
We will add to this soon….