Still more rear axle cover.

January 12th, 2014

Busy weekend this weekend so I got quite a bit done.  I started making the top part of the rear axle cover. I cut a piece to fit cut slots near the edge before bending over a flange. The slots match up to the position of the swages I hammered into the firewall. The slots then let me hammer the flange so it would clear the swages.


I was mucking about with that and Joss came over and pointed out I had done things the hard way.  Instead of starting by making a curved edge then having to make the second piece fit I could have started with flat pieces that you mark off against each other. You then remove a small section in the middle and then roughly bend the edges over 45 degrees to get the two edges to meet. You weld the edge THEN hammer it all smooth and into the curve.

In the end I mostly did that anyway as I laid on the top piece, marked up from the vertical and trimmed it to fit. Then I bent over it’s edge till it overlapped the vertical piece and marked where to cut so the two pieces fitted together. The other thing I did was lift up the vertical piece so the curve was higher than the tube. That was I didn’t need any odd shapes in the corners. Pictures makes all this clearer.

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I also hammered some swages into the flat piece. These aren’t seen since the petrol tank sits above them. Next I gas welded them together. I did this with the frame off the car standing on it’s end. Since this is zinc coated steel I wear a mask when welding it to avoid breathing in any nasty stuff. The zinc burns off and is toxic. You can see the flange on the flat piece and how it clears the swages in the firewall. I will borrow the spot welder and spot this flange in place.

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Then it was a matter of grinding and hammering the weld to get things nice and smooth again. You can see how lifting the curve means I have a little gap just above the axle arch I will need to fill with a small piece of steel. I still need to make the new floor and finish welding everything together and tidying it up.

I also made the little semicircular pieces that fill the gap where the firewall meets the side tubes. These are brazed to the frame and will be spotted to the firewall. Another small job was welding on the nuts on the transmission tunnel. The tunnel is attached to the floor so it needs to be detachable from the firewall if I ever want to remove the body. Captive nuts mean you can easily screw the two together from inside the car.

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I also did some experiments with an old banana box to work out how the petrol tank will go. It will sit on the flat part above the rear axle. I’ll curve the front so it matches the curve in the boot. The tank needs to be able to go in through the boot opening so it can be removed if that is ever necessary. A quick test shows I should be able to fit a 6 gallon tank in there no trouble. That’s 6 gallons total volume so say 5 gallons (22.7L) usable which is the same as a normal Austin 7 (the early ones were 4 gallon I think)?

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