A Cornish mine name that couldn’t be resisted…
For my 80th birthday Jane bought me a mangle wheel. It was big, heavy and green and she carried it from Manchester to a posh Bristol hotel just for me. It caused quite a stir in the lounge.
At first I thought it was just too big and the crankshaft would need to be about a foot high but then I remembered seeing huge engines in museums with half of the flywheel sunk in a pit. Bingo! (I mean ‘eureka’)
Now I don’t like wood, you can’t weld it, thread it or rely on it to stay put, nasty stuff that keeps splitting down the grain and the worst kind of metal imaginable, but having priced up suitable boxes on Ebay I found some old damp wood in the garden and set about becoming a carpenter. Hence the lovely base that still needs finishing!The wheel was far too big for my lathe but I disked off the rim and sleeved the bore and it came up quite well. I kept the original paint finish.
I found a decent piece of 25mm brass tube for the cylinder and set about making a piston and slide valve until it occurred to me that this bore/stroke was going to need a lot of steam. Hmm. So I cheated by inserting a bit of 15mm copper tube inside the lovely brass ‘cylinder’ to make a much smaller diameter power cylinder.
Next a steam boiler was needed and I was stuck for a suitable pressure vessel but remembered using a pressure cooker in the past so I bought a lovely shiny new one on Ebay for under £10 and added the necessary fittings, copper steam pipeline and even put a bolt through the lid fitting for safety. Heat came from a camping gas stove and the whole set up looked quite spiffing.
That small diameter cylinder and piston needed a bit of pressure to get going and I let it slowly build up to around 30psi with no leaks showing when – bloody ell there was a terrific explosion!
Something hit me in the face and the room went dark.The pressure cooker lid had blown straight off, smashing the overhead light fitting and almost penetrating the ceiling. Best I don’t dwell on this part of the Wheal Jane development but I won’t be using any cheap Chinese cooking pots ever again.
I think pressure cookers are designed to work at about 2psi and so my 30psi acting on the 10 inch lid was perhaps a trifle ambitious, you do the maths!
So plan B was necessary and a chance advert in the local website led me to buy four big empty fire extinguishers – good solid safe pressure vessels. After unscrewing the top I discovered that they are plastic lined and so useless as a boiler. Sh1t back to square one.
Small 2kg powder fire extinguishers are not lined and although the in/out fitting was a bit small I was getting desperate by this time and so opted to mount one at about 45 degrees to allow a useful water level and heating area. I bought a new one and let it off in the garden, it’s amazing how much powder they hold when you are trying to avoid attention. Then I inserted it in the side of one of those big plastic lined ones.
Another camping gas burner fitted in well and this time nothing exploded, Wheal Jane puffed merrily.
Note fake brass cylinder and double fire extinguisher boiler.
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Bernie's Engines 