Mindsigh

Steam engine – GAGE VR1A Graham Industries

Posted by Jerry on March 11th, 2008 — Posted in History, Journal, Steam, Technology

Yes I’ve been neglecting this blog a little, but grab a cuppa because this is really neat 🙂

It was my birthday recently and a pleasant surprise arrived right on time from the USA. It was a package – tantalisingly box-like

When I opened it, out came a package of metal bits and a reassuringly large instruction manual from Graham Industries – a detailed working live steam model engine. It is a single-cylinder, double acting engine with a stephenson link reversing gear – the sort you get on steam trains.

I had a rough idea of how this worked, but was always keen to see it in a tactile way to really understand the principle – which is outlined here, but is better illustrated here.

I borrowed a beading tray from Sharon to prevent the loss of small parts – the bolts are tiny and in good scale with the engine.

And so I set to work on the assembly. The manual opened with a lovely line drawing showing the relationship of components and separate drawings of the valve gear

The cylinder and piston assembly was first – and the manual was well illustrated with step-by-step photos. The package even included proper paper gaskets to ensure proper sealing.

Then came the valve gear – a slide valve that would move up and down to reveal the ports in sequence

Then it was time to assemble the frame

The crankshaft followed with the valve eccentrics, the beautifully machined brass flywheel, and the connecting rod was added to the crank-pin

And finally the engine was complete. The detail is fantastic. Each of the bolts holding moving parts runs in a brass bushing to minimise friction, and the engine runs on fairly low pressure air or steam.

Here is the completed engine.

I did a test run first using a tiny air compressor run off my car’s cigarette lighter, and it ran briefly before one of the bolts vibrated loose on the reversing gear. This was fixed with a light dab of loctite, and then I adjusted the valve timing lightly (yes it is fully tunable!) until it ran well in both directions from the air compressor.

But a steam engine isn’t a steam engine unless it runs on steam is it? So, not having a boiler to hand I went for the next best thing – a milk steamer from a cappucino machine – it had a steam valve to act as a throttle, and with a couple of bits of clear plastic tubing (fuel line) I stepped down the size so it would fit on both the milk steamer and the engine. And within moments, the engine ran smoothly – without the harshness I found running it on air – and without the problem of possibly setting off the smoke alarms!

Here it is running on steam

Cheers
Jerry

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