Still bonnet.

February 8th, 2018

This one bit (well four bits) is taking ages! But there is  alot of making in it I guess. Especially when you’re not 100% sure of what you’re doing. This was done over 3 or 4 nights.

I first marked out the top for the fingers that wrap around the brass hinge pin. I referred to my drawing and checked everything many times to make sure I got it right. Would be annoying to mess up the panels now!

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It gets a bit tricky at the ends as you need to finish the hinge in from the end of the panel because the edge needs to be clear where it touches the rubber on the body and radiator surround. I carefully marked the bits to be removed. I then cut out all the fingers using my hand nibbler. I found this caused way less distortion than if I used snips. It took about 800 nibbles to do them all. I then cleaned things up with a file.

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That all took a night. The next night (day actually, it was a public holiday) I cut out some flat sheet for the bottom panels and then marked each so top and bottom were matched. I then used each top to mark the fingers on the bottom one. Theoretically if I did everything perfectly you could interchange the bits but that’s never going to happen with something handmade like this. Well, certainly not me on my first go.

Tonight I came home and put the bottom halves to one side and did the folding on the top. I want to do the top first so I can work out exactly where the flange on the bottom one needs to go. I want the gap to be as small as possible I think.

I don’t have a folder so I had to do the next bit by hand. I just used steel flat bar and clamps on a flat piece of chipboard.

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I am not sure what the proper order for doing these folds is. But this is how I did it. First I bet the 180 degree fold. First bringing the edge up 90 degrees then hammering it right over. The intermediate stage looks all wobbly but as long as there is a nice break on the fold it hammers down fine. I found after hammering it one panel had a slight curve to it so I put it through the English wheel and that smoothed and flattened it out nicely. The part where the pin goes has to be straight of course.

I then bend up the fingers that get hammered around the pin. I used some flat bar that I have ground a curve onto one edge. The fingers were bent around that so that the bottom corner is round around the pin.

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I found using my flat welding pliers made it easy to pull the fingers up and around. That worked very well.

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I did this to both top panels and then did a test fit on the car. I knew the panels would distort a little having the edges folded but they did so in a good way. Having that edge nice and straight pulled the panels in nicely. One had a slight hollow in the top but I was able to take that out on the wheel. The doubled over edge is nice and strong so the panel doesn’t distort as much when wheeled now. One thing I forgot is I need to trim the folded over part on the edge. I think the edge needs to be only a single layer thick where it touches the rubber so it sits nicely flat on the rubber. I can cut and file that away if needed.

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The panels fit the car very well now. A little more tweaking might be needed once I do the bottom parts of course. But they are going to be held on with straps so that’ll pull it all down tight.

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Those probably aren’t the straps I will use, they just give an idea.

Next is doing the bottom halves. The tricky bit on them is they need a joggle so the top panel and the bottom are flush with each other. Again without a folder that is tricky to do neatly. But I think I can use the bead roller and it’s flanging dies. Normally when you roll a bead into a panel it will distort it since you are stretching one side of the metal sheet more than the other. If you have a wheel you can pre stretch the bit you’re going to put the bead into and that minimises the effect. I did some tests though and found the flanging dies didn’t seem to make the panel curve. Maybe since it’s putting a bend into the panel, not a stretch. So I will probably use that. Then it’s just another 800 nibbles to make the fingers.

It always amuses me how dirty you get playing with what looks like clean aluminium sheet.

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I’ve also ordered the edging rubber from David at A7 Components in the UK  as well as new clutch toggle pins so I can get that finished then send it all off for balancing then I can finally build the engine.

The other thing I want to do it clean up the radiator. I know it doesn’t leak so that’s good. The top tank is a bit dinged. I am thinking I might be able to pull some of that out somehow. If I can get something behind the dent I can tap it out from inside. Or I can just drill small holes maybe, poke in a bend wire to pull out the dinged bits then solder up the holes.

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