Posted by jerry on June 11th, 2007 — Posted in Journal, Steam
A while ago I bought a small oscillating engine off eBay for less than half the price of an equivalent mamod or wilescoengine. This one was made in India. It isn’t finished as well as a willesco, but it was delivered promptly and looked quite serviceable.
Being a new, previously unfired engine I felt there were a couple of stiff points when i rotated the flywheel by hand. So I unscrewed the bolt holding the piston connecting rod to the crankshaft and carefully withdrew the piston from the cylinder. Then I sprayed with Tac chain grease on the piston and all moving parts – including the valve surface. Then I removed the filler screw and safety valve from the boiler and inspected them. I filed down some roughness on the mating surface on the boiler, and inspected the boiler carefully for any dents or obvious breaks in the seals. It seemed solidly built and about twice the size of the equivalent mamod engine.
After reinstalling the piston I used a small funnel to half fill the boiler, then reinstalled the filler screw and safety valve. Then I got a couple of firelighters and placed the in the burner tray and lit them, placing he burner beneath the boiler. There was a bit of smoke and a lot of flame and after about ten minutes there were definite kettle noises emerging.
I tried the whistle and saw a blast of steam, but no whistle sound. I shut the whistle off and waited a couple of minutes before taking a tentative spin of the flywheel… And here’s the result
There is no maker’s plate, but I’m told that an Indian firm makes them. The boiler has a very large capacity – around 600mls (an imperial pint) and with the firelighters looks to have possibly close to an hour’s duration once steam is up. The engine runs smoothly, and I suspect it will run faster once it is fully run-in.
I had been re-reading Willim Gibson/Bruce Sterling’s book The Difference Engine and recalled the one built in the London Science Museum which was built as far as possible with the metallurgy and tolerances available to Charles Babbage in the 1820s. And the machine works well.
Seeing the (re)production machine which weighs in at around 2.62 tonnes and occupies an area 12.65 feet by 6.65 feet and 8.21 feet high – this is a seriously impressive machine. It can solve 7th order polynomials to 31 digits of accuracy – certainly greater than the average pocket calculator today.
But then a quick search showed that some enterprising souls have been making good use of multi-modal construction toys like Meccano® and Lego® to re-create at least part of Babbage’s Difference Engine Number 2.
Tim Robinson set about building his in Meccano® to achieve a successful working model – eventually he hopes to power it with a Meccano (Mamod?) steam engine to realise fully the steam-punk dream.
Andrew Carol’s approach was different, setting about solving the challenges posed by flexible plastic components to produce a 3 order polynomial machine built in a modular way using Lego®
And in 2000, nine years after the Difference Engine No2 was completed, engineers at the London Science Museum completed the printer element of the engine, thus giving hard-copy output to the set of numbers.
All up these are a great way to come to grips with a remarkable precursor to modern computers. Babbage stopped working on his Difference Engine No2 in order to devote time to develloping the true precursor to the modern computer – the Analytic Engine – which, thanks to Ada Lovelace’s programming genius, would have been able to perform any kind of operation, using IF/THEN logic not just the pre-set operations.
One could well speculate, as Gibson and Sterling have done, what might the Victorian era been like in the UK if the Analytic Engine became as widespread as computers today. I’m inclined to think, however, that it would have required a social change to see the need for these machines before they would have emerged into wider society’s use.
Having just encountered the wonderful steam models page of Forest Classics in the UK I was amazed at the range of steam models now available. It used to be mamod and more mamod, but little else – now it seems there are many manufacturers of high quality kits and assembled live steam models – from stationary beam engines like this one from Sussex Steam Beam & Mill Engine Kits
to full-on radio controlled live steam cars, like this model 1907 stanley steamer from the MiniSteam company…
After seeing a mate run his radio controlled petrol driven model race car up and down our street, I thought nah, I prefer steam!
and recalled the one built in the 
