Framing and more cardboard.

December 8th, 2011

The last week and a half or so has been spent bending tube and tacking things together. I started making the easy hoops, the two front ones. One at the firewall and the other at the instrument panel. These were fairly simple to do but it still took me multiple attempts. I used cardboard to draw out the patterns then used my bending thing to make the bends. To work out where to make the bends I would make one side first then used a length of wire bent over the side of the tube from the start of the bend to the centre point. If you think about what the metal does in a bend the inside of the curve shrinks, the outside stretches so the middle should remain the same. By measuring the length there I could then straighten the wire and use it to measure where to make the second bend to make the frame symmetrical.

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Bending frames.

These two frames were attached to the floor by making small brackets from some angle iron. I then screwed to the base board. The front two frames have vertical sides since the front of the car is vertical.

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IMG_1162_1 Front two frames.

I made the first two frames this way and was attempting to do the rear ones in the same way and not having much luck so luckily Joss came over to advise before I got stuck or went too far wrong. I am definitely too anal about things. My approach is to measure everything. His advice was to just bend things so they look right. And to run verticals first that I could bend into the correct angle then worry about getting the curve on top. I was trying to bend the whole thing in one go. The frame is steel of course and the beautiful thing about steel is you can use as many bits as you like and just weld them together.

So I made up some verticals and some more angle brackets but from thinner steel so I could bend them easily. I positioned them more or less evenly along the sides of the floor. They are just held in by a single screw and they go down past the ends of the floor. I attached the tail to where that should be. The hoop here is vertical but the tail will be angled somewhat. This is done in the aluminium skin. I then bent the backbone. To start with I use a single length so I can get a smooth curve from the front of the car to the rear. Eventually the cockpit section will be cut out of course.  To bend it I just put it in the vice and pulled it round. No formers. No measurements. I just hand bent it till it looked right.

IMG_1167_1 IMG_1169_1 Verticals.

IMG_1172_1 IMG_1178_1 Bending backbone tube in the vice.

So that the sides aren’t just vertical slabs I tipped them in somewhat. I don’t know how much. I just bent them so it looked right! I started at the tail then used the batten again to bend in the others to fit the curve. It goes from vertical at the front to not quite so vertical at the back in a progressive way. Am getting better at the whole ‘bend it till it looks right’ thing!

I did go back to some measurements though. Just to make sure things were symmetrical I pulled apart half of my wooden frame and reused the bookends and the sticks and all my clamps to get the two halves of the car the same. When building a car this way you can’t have too many sticks or clamps!

I then hand bent the tubes that make up the top of the sides. I made one side first and made sure that was correct by bending it to the outside of the verticals. I then cut the verticals off at the right height to give the correct curve and then tweaked the curve of the long tube to make it sit on top of the cut off verticals by tightening it slightly.  At this point you are only making tiny adjustments to the tube just by bending it over a knee or the edge of the bench. If you see it move it’s probably bent too far!

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Side tubes in place.

To make the other side I took that tube outside and traced around it on the footpath. I then just bent another tube to fit that outline (again much to the amusement of people wandering past). I then tack welded everything in place.

This provides enough frame to see if the shape is right so out came my corrugated cardboard roll again and a remade the skin to fit over the frame I had so far to see how it looks. I find it easier to bend the cardboard to fit rather than trying to make a frame first then fit the cardboard to that. I rolled the car outside to see what I had now.

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Getting more idea of shape.

I then had to get the help of a friend to get the rest of the shape right since I couldn’t make the curve under the bottom of the car right by myself so I got my friend Grant to come help me again with his artists eye.

The first thing he suggested was the back was too high. I agreed so I dropped the height behind the seats about an inch. Dropping it down took it back to my original wooden model height so I was actually too high. With the frame all tacked together changing things just means you file off the weld till it breaks loose and then you just bend the tube to the new shape using brute force. We then took the car outside again and this time turned it sideways so we could get right across the road to sort out the profile.

IMG_1193_1 Car sideways.

I am sure there will be a car accident sometime with people slowing down to see what I am up to as they drive past. Lots of double takes. Those on foot seem to like it though. Grant and I tweaked the bottom line of the body till it looked right.  We then did the same for the profile around the cockpit. We used masking tape to mark things out. Once it looked right I cut away the excess cardboard and we painted the cut-out for the cockpit black so we could see what it would look like.

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Bottom curve defined.

So this is what I have now. The radiator is tipped forwards a bit in the first few pictures but that’s easily fixed.  The next step will be to bend the bottom tube under the floor. That one defines the bottom shape of the body. I think in the pictures above the bottom of the tail is a bit too high still, perhaps 1/4 to 1/2 an inch. So I might make that a bit deeper. We couldn’t use the batten to run a smooth curve all the way across the bottom since the rear axle is right in the way. I think the curves on the top and sides of the tail look just right and I am very happy with them. When the body is lowered a few inches and things like cycle guards and lights are added I think the body will look quite low despite the fact that the car is kind of bulky. She’s very chunky but  like her! I’ve always liked curvy girls though.

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It’s a bit hard to see above but the sides aren’t vertical. I think the tail will look a lot better all smooth and not segmented. I have to do that since the cardboard only bends in one plane easily so it needs to be cut into thin strips to get the curves right. The body is very narrow. The steering wheel is actually outside the body. The car really looks like a 1930s car going fast. Almost a caricature.

So far I have only cardboarded one side. It is an interesting look. You can see how minimal the frame is. There won’t be too much more. The frame is something to hang the skin onto. The frame is just a skeleton. The skin defines the shape.

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