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A Special Builder's Notes

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08 December 2018

Fun With Funnels....

... though fun was the last thing it turned out to be. It was a job that had been doing the rounds of successive fabricators, each politely declining the work until muggins here, thought it would be an interesting exercise. Fortunately, having committed to the work (and a tight deadline) enough of my engineering friends took pity on me to help bring about a successful conclusion.

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Using the etched lines as guides, a few hours on the brake press saw 80 of these developments ready to be tacked together. The upper band was also rolled ready for joining.

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As the developments were only 1.2mm mild steel and not always completely abutted, I tacked rather than continuously welded the seams. Then, over a wooden jig, I persuaded the welded band over the funnel (which had the added bonus of pulling the funnel properly into the round) tacked around the circumference and finally tapped the surplus 10mm into the shape of the body.

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3 metres of steel pipe was chopped up to make the bottom tubes - my chop saw has now paid for itself - and the press tool was turned up by Chumley (a half-dozen finest Norfolk sausages, 6 rashers of excellent streaky and 4 homemade burgers did the trick - remember I was on a tight schedule) and it worked perfectly, the tubes just resting in the bottom of the funnel ready to be tacked on the outside.

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This was a stage I was pleased to arrive at - the fitting of the bands being especially irksome. The peening over of the surplus looked like being a long old job as well, so I spent an hour making up a planishing tool for my air chisel. After about 10 seconds, the head fell off the stem (dissimilar metals - duff welding) so it was back to the Armstrong method. Good practise for the Alvis body!

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The whole lot went off to the powder-coaters, coming back all shiny and, more importantly, ahead of schedule....

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.... leaving me time to get on with the Alvis drawings. I have to say, it's no easy task and, having now moved on to the front and rear projections, what seemed like a relatively simple procedure, has proved quite difficult on paper. A sketch on the back of a napkin is a doddle but, when you have to get down to the detail - where a panel starts or ends and how it blends into the next shape - is a bit of a headache. I think only by making the model, will I then properly arrive at the form. I've got the profile and I can more or less extrapolate from the drawings so far, the 3-dimensional figure. Tweaking that and then scanning to make the buck formers, is my plan. The model will be about 850mm in length (roughly 1/5th scale) so should be a reasonably accurate representation.

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A visit to Leon and Awkward's workshop for the start-up of the rebuilt Climax provided an excuse to get away from the drawing board. One snag...

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... a bolt left over, though I have my suspicions that some joker might have dropped that in the box of bits. Talking of jokers...

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.... next door thought the funnels were great fun.

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