More frame finishing.

February 26th, 2013

WithHampton Downs about a month away I better get a wiggle on so I am working on the car a lot now.

Last week I stopped off at the sheet metal place and got some 2mm steel to make my front shock arms finally. I cut two rectangles and pop riveted them togther then blued them and marked out the arm shape. I cut them out using a thin disc on the angle grinder then finished them with the bench grinder, angle grinder and hand files.

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A short length of 19mm tube joins them and provided space for a rubber bush. I brazed the tube in place. The arms need a slight bend near the circles so they sit parallel when bolted onto the shock. The arms themselves are about 1/4 of an inch longer than the originals so they are long enough to reach to the axle mounting point.

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I painted them black and bolted them in place. This really locks up the front end as now the axle can’t swing from side to side although it will still move in a slight arc when going up and down. Longer arms (say out to the radius rod mounting point) would reduce the arc. How much difference does it make in real life? No idea!

Another little job I did was weld up the mounting holes in my little steering column bracket and shift them up. The bracket fits much better now with the tubes parallel when the bolt is done up.

I also finally  got around to machining up a punch to do my brake rivets. I used a piece of steel bar rescued from a dead printer. I machined a profile in the end of the bar loosely based on the one shown here:

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Mine was a bit rough but it worked fine. The notch in the outside of the punch is to clear the brake spring attachment points. I  used a second punch with round end the same diameter as the rivet head as a small anvil in the vice and hammered against that. I took apart the front hubs again so I could fit the shoes  but then discovered you can’t bolt everything up then attach the brake levers later on as you can’t get the lever on over the adjusters when they are in place. There just isn’t room to fit them over the shaft as the axle gets in the way.

My brake levers are not the best so I want to try to get new, reproduction ones as these are fairly important! Until I do I can’t assemble the front brakes and put the wheels back on. In the mean time I have touched up the paint (lightly) on the wheels from where I had to sand it off after the damn things got stuck on the hubs due to overly thick paint! If I don’t get new levers in time I can temporarily fit the old ones (once I get new cotters).

I then looked at making the bottom of the tail after Joss suggested I needed a tube there to attach the boot floor to and define the base shape of the tail piece. I drew out the right lines on some cardboard and chose a radius for the tip that looked about right.  I bent a tube to fit and it seems right but the bend being so tight meant the tube was very crumpled, even using heat.

So I tried something I always wanted to give a go. That is filling a tube with dry sand, plugging the ends and bending it that way. The sand fills the tube and stops it collapsing on itself and kinking.

I made two wooden dowel plug and hammered one into one end a length of tube.  I then filled the tube with sand. The sand needs to be very dry which mine is as I use it as a base for my moulds when casting metal. When scooping up handfuls of dry sand I also scooped up a totally dry dead weta!

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With the tube full I hamemred another wood plug into the open end to close it. I then heated the tube to red and bent it around a suitable former held in the vice. It worked brilliantly! Was easy to bend and the sand does work and stops the kinking. It is also easier to heat the tube as it seems to take in more heat and hold it there.

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You can see the sand filled bent tube on the left above and the unfilled, kinked tube on the right.

I was able to tack the tail piece in place then got distracted by the arrival of a huge truck with all my new roofing iron (house needed doing)  on it. I had to stop to help the truck driver who had to use the crane to lift all the iron over the footpath and the trees in front of my house into my front garden. The reach on those little cranes is impressive!

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Tonight the roofers were still here when I got home so I went out to the garage. I finished off brazing the tail piece on (out on the footpath in front of my garage since my garden is a mess with old roof stuff). I also spot welded and then brazed the rear axle cover part of the rear firewall in place.

IMG_3494_1 IMG_3495_1 Tail piece.

With that box spotted and brazed into position the frame is really quite solid but still not too heavy (I hope). I need to remove all the flux still and sand things down a little. Where I had two layers of metal spotted together I first sprayed between them with zinc rich weld through primer. This actually seemed to help with the spot welds too. When welding and brazing I wore a respirator to avoid breathing in any nasty zinc fumes.

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There is a small gap in the corners of the box but a comple of small metal covers should take care of that. I still need to get some steel for the boot floor and look at folding up the transmission tunnel.

Also to do are make up an instrument panel and glove box (a fiddle little job apparently) and braze on mounting points for that.

I will also make up some reinforcing plates for where the front valences mount to the firewall.

And make up rounded corner plates for the boot opening. Then footwell floors as well as cutting a hole and making a battery box in the nearside of the firewall (for which I might need to get a suitable 6 volt battery first to make sure it fits)!

Eventually I can paint the frame and then finally, the last step is adding the aluminium skin.

I bought some Pewter coloured (light grey) Wattyl Kill Rust enamel to paint the frame with. Bunnings used to stock it but now don’t so I got mine fomr Supercheap auto instead. It comes in both tins and rattle cans. I can thin the tinned stuff and spray it with my gun and compressor and the rattle cans are perfect for touchups later. I used the same paint for the wheels (in black of course) and the spray cans made touching those up dead easy too. The whole chassis is done in the same paint.


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