Steel.

November 29th, 2011

Joss came over to see the car and despite us not being able to get her outside he said I was ready to start on the frame. In the weekend I headed over to Steel North Shore in Glenfield to get some tube. I bought 8 lengths of 16mm by 1.2 wall tubing. The lengths were 5.5m long so they chopped them in half for me so I could fit them in the MGB (top down of course). I also bought some 25mm by 3mm strap to make lugs from. As well as some scraps of interesting looking steel they had in a junk pile. Well, if you like steel, and I do, you can’t pass up good bits of scrap! All up it was about $250NZ.

IMG_1117_1 Steel.

I didn’t get to do much on the car in the weekend. Sunday I went with Joss to visit Richard and see his two Austin 7s. The Dieppe and the H car. An interesting afternoon was spent looking at, under and in those cars. I did manage to brace the wood frame then remove it from the floor in one piece to be set aside for reference to later.

IMG_1121_1 Hello chassis my old friend!

I also cut out the floor with a jigsaw and bolted it to the chassis. More will be removed from it later but for now it provides the plan shape and forms a platform to build the frame onto.

IMG_1120_1 IMG_1126_1 IMG_1128_1 Floor.

With the excess cut from the floor you can really see how narrow the body is.

IMG_1127_1 Floor bolted down.

Tonight I started playing with the steel to work out how best to bend it. First I tried bending it by hand free form over a metal pipe 4 inches in diameter. This does work if you are careful but it is hard to get consistent bends. I found I had to do it carefully. If I put the pipe in the vice and just tried to bend the pipe round with the end pushing against the bench the pipe would kink. Now most people would say you either need heat or to fill the pipe with sand so it doesn’t kink at this point but I was sure it could be done without all that carry on.

IMG_1130_1 IMG_1134_1 Bending pipe free form.

I had some success doing this. I made a bend that seemed right then drew a pattern on the floor in chalk so I could bend the other half of the pipe. Actually I found the garage floor too uneven to draw on so I went outside and used the footpath in front of my garage much to the bemusement of people walking past who probably thought I was mad.

IMG_1133_1 Pavement pattern.

I did manage to bend a frame that mostly worked but I found the bends were inconsistent. I am not sure how perfect these frames need to be but for me they need to be perfect. Apparently I am somewhat anal about these things. So I decided to try a method I saw online somewhere. I cut a former from some MDF to give the curve I needed (traced around a handy thinner tin). Then I clamped that in the bench vice with the pipe and just pulled the tube around it. It bloody worked! This actually works really well and gives a nice consistent bend. The tube does flatten slightly but that is because bending it is forcing one side to shrink and the other to stretch so the pipe profile changes. With the wood though the profile is even.

IMG_1139_1 IMG_1141_1 IMG_1143_1

Bending around a MDF former.

IMG_1137_1 IMG_1138_1 180 degree bend.

I was able to bend a neat, even, 180 degree bend 4 inches in diameter. I used the same paint tin to work out the curves on the cardboard body so these curves should work in steel (high-tech!).

Next I will make up some patterns to bend the tube to from cardboard. I need to make four hoops. One at the end of the bonnet/firewall, one where the dash will be, one behind the seats and one right at the end of the tail. The hoops will extend below the floor since there will be a lower rail that defines the bottom of the body attached to them. There will be a sill rail attached to the floor and 4 to 6 inches above that another rail. The space between the two will be covered in aluminium sheet to create a sort of girder to give strength to the body. There won’t be many tubes. Just enough to hang the aluminium skin on.

Leave a Reply