There are some extenuating circumstances, the main one being that Sean and The Gang stayed with us for around 6 weeks during December and January prior to them setting off for Oz. It was great fun having them here, though a bit sad for everyone when they left - however, with the techo-wizardry available to us these days we can message and talk any time we want. A bit different to when we went to South Africa in 1970 and letters took around 6 weeks to arrive and phone calls were so rare that you had to book each one in advance with the exchange.
Anyway, things are gradually returning to normal and the hammer has been in action again in the workshop, starting with the great aluminium melting experiment.
I wanted to see how easy it might be to melt aluminium in order to cast pieces for the new engine. After lots of searching around I managed to locate a couple of metal paint tins, punched a few holes in them and welded them one on top of the other. The idea was that the top one holds a bed of charcoal, and the bottom one feeds a blast of air from a hair drier through the hot charcoal to make it hot enough. I welded a long handle on to an empty bean tin and filled it with all the offcuts of aluminium that I could cram in. Right, lets get started.
First, set a small fire in the top can and get the charcoal going. While that was cooking I gaffer taped the spout of the hair drier to a length of plastic pipe and taped that to a hole in the side of the lower paint tin. So far so good, charcoal cooking nicely by now, so insert the bean tin into the fire and pack some more charcoal around it. Time to apply some wind, so on with the hair drier.
Those who have seen the NASA space shuttle taking off will have a rough idea of the result, an absolute tower of blue-white flame at least three metres high accompanied by a roar that would scare a polar bear. I managed to keep most of my clothes and body hair intact while realising that the blast was eating the charcoal at an incredible rate, at the same time generating enough heat to set fire to the moon. I couldn't get near enough to add more coal, so I switched off the blower and re-fuelled, at the same time noticing that the heat had started to melt the plastic pipe. Hmm.
|The furnace afterwards|
|Castings in flower pots|
Once I had decided to use bar stock I have managed to make some fair progress on the body of the engine. The crankshaft is now made and reasonably straight - its more complex than most engines because this type of 2 stroke engine needs some positive air pressure to force the exhaust gas out of the cylinders and the fuel mixture in, so the engine has a supercharger arrangement for this purpose. This also allows for some 'ramming' of the fuel mixture by having the intake crank slightly offset from the exhaust so that the intake ports are still open for a while after the exhaust has closed. Time will tell if it works or not, but thats how the original full sized engine was made.
|The assembled crankshaft with thrust bearings|
|Crankcase seen from underneath with the oil pump in position|
|One of the part finished cylinders assembled with the pair of cylinder heads|
|Crankcase with crankshaft and rocker arrangement in place|
The cylinders are going to be a bit of a problem, mainly because they are so big - the bore is 30mm and the stroke is the same, but because there are two pistons in each cylinder each one is twice the length that a 'normal' cylinder would be - these are around 90mm long, so I had to make a new set of extra long boring bars to make the bores. I also don't like working with cast iron, its filthy stuff and very dusty so it clogs up everything it touches and its a pig to clean up afterwards.
Not only that, but the iron I used has a very hard and coarse grain, resulting in a surface finish that is way too rough to use without further work. After much chewing on this I have decided to make a grinder to fit on the lathe toolpost so that I can grind the bores smooth - it doesn't need to be very precise as I will grind the bores and then make pistons to fit them. More on the grinding machine next time.
In between breaks on the engine, I have been making some more woody stuff. I wanted to make a small ring box, but didn't have enough wide timber for the flat part of the lid. The Boss suggested that I make an insert from material instead, and the results are pretty good.
The ring holder part is a series of blocks of foam glued to a card base with spaces between each block, and the whole lot then covered in black velvet - simple and quick, and it seems to work well.
I am planning to expand this idea to make maybe some watch boxes or small cabinets at some point, watch this space.
I have also been giving some thought to my future artistic endeavours as well. This deep thinking has been prompted by a couple of conversations with shops - the first took one look at my ring box, and immediately said "it should have feet on it", then proceeded to tell me in great detail how the design was all wrong. Hmmm. Then another shop owner said she was interested in selling some of my stuff, so I sent her a load of pictures and got massive enthusiasm from her: so I arranged to take over some samples for her to see and when I spoke to her later she said "the boxes are lovely but they are too chinese". Wot? She had already seen the pictures, and I had explained that I could make them in any material, but she wasn't listening. It appears that she wanted 'shabby chic'. Grrr.
This got me thinking. I like to sell stuff, because the money helps me buy materials for other things (like the engine) and also affirms that people like my work enough to throw money at me. At the same time, I don't want to be churning out multiple copies of the same box/picture/butterfly/etc on a daily basis, especially since its the small stuff that sells best and there's very little money in that. What I really like to do is to make one-offs, single objects that I make because I feel like it, not because I think someone might buy it, so I think I'm going to do more of that and less trying to persuade shops to sell my stuff. Once I have a few pieces made, I may try taking them to a pukka art gallery to sell, although these tend to sneer at things made of wood - that's craft, darling, not art - or I may just keep them. More on this as I develop the idea, but I have some half formed plans burbling away in the background....
I've done some other stuff as well, notably a sign for the village. During the arts festival last summer, villagers made a family of three people and a dog out of willow, and eventually got round to erecting it in the middle of the village. I was asked to make a sign for it, so I found a nice bit of oak and dusted off my signwriter's brushes and mahl stick, and this is the result -
Considering I last did signwriting in around 1976, it turned out pretty well, even though the willow sculptures are not my favourite thing
Last, we had the first kart meeting of the year a couple of weeks ago. It was very, very wet, but the biggest problem was the low cloud which made it impossible to see the track
|The track is the other side of that fence, honest|
That's it for now. Jon's wedding is on Saturday, looking forward to that, it should be a fun day for all concerned. Next time should have some details of the tool post grinder and some more progress on the engine, plus maybe some more arty stuff. Try to keep the applause down to a dull roar, please.