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Letting off Steam

Updated: Apr 12, 2022

Originally posted by Jim K2BHM.

People have been asking about my Steam Engines that I have been talking about.

pmmodelengines.com has been selling casting kits for about 30 years now. The red and black Vertical engine, their #2 kit, was a kit I bought about 25 years ago. It made it to about half completed over the years. I found it several months ago and finished it. The green and yellow engine, their #3 kit came from my friend Ken, WB2TDG. I made that kit next. They run nicely on 5 to 10 psi of air. I have video, but apparently we can only put video here as a link. It refuses to download it like a picture. So, with two nice engines purring away on compressed air, the next step is to feed them some Live Steam. PM sells model boiler kits as well as accessories. The brass unit in the center is a pump kit used to pump water from the tank on the right to the boiler. Here is a picture of the boiler kit parts.


So, there is a lot of work to get from here to PM's picture of the finished product.



The Steam Bonnet is done.


Black plastic from P&T was used to make a fixture to hold the smokestack funnel for machining.


A mandrel was constructed to hold the main boiler tank.


Making it easy to drill all the rivet holes and ports.


My boiler, ready to be piped into the system. Now to make the fittings and valves!


Various kits take different levels of work and expertise to complete.


The bag on the left has a brass casting "Fitting Tree". You cut out the fitting and drill through with a hole the size of the inside of the tubing you are using. You then drill or drill and tap the fittings to solder or thread the tubes into the fittings. The bag on the right is a kit of 4 valves. You can machine them as straight through or right angle valves. The "Instructions", shown below, are mechanical drawings that give specifications, dimensions and tolerances of the components and how to assemble them into the finished unit.


The drawings for the valve is both sides of an 8-1/2 X 11 sheet of paper. The engine plans are 2 sheets of paper, 2 X 3 Feet. The boiler is 3 sheets! The drawings describe the finished part. It is up to you to decide how to actually make the parts, as in what machine to use, what tooling to use and how to hold it. Primarily driven by what you have on hand, your level of experience, and your creativity.

With everything going on now.... Corona Virus, Quarantine, Shortages, Protests... It's nice to go out into the shop and get lost in a project. The level of concentration required to plan and execute making the components leaves little room for worrying about anything else!


Jim K2BHM




Videos of my engines running on compressed air.



























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