On with the build part 2…

In my last blog I talked about how I entered a race and have thus had to get cracking with my build. You might want to jump over and read that first HERE.

The next stage was the steering components and the completion of the front and rear rolling axles. I started with the front stub axles. These were kindly made up for me by gravity racing legend and useful engineer Andy Ash – cheers Andy! All I had to do was line the parts up – the bearing carrier and the axle – and TIG weld them together. As ever, lining small parts up was the hard bit and a bit of head scratching was required before they were lined up in a way that wouldn’t move during welding, and so that I could ensure both axles were done the same.

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Here is the bearing carrier and stub axle. I clamped the axle on top of a bit of 5mm bar, which was about perfect for vertical spacing. Then it was a case of lining things up horizontally by eye (a couple of us had a look at it 🙂 ) before tacking the part in place with the TIG welder.

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Each axle was tacked in place with three good tacks. Now it was a case of completing the welds all around, taking care not to get too much heat into the part and potentially distorting the bearing carrier so the bearings wouldn’t fit. Lots of waiting between short welds to allow for cooling. Lots of tea.

So they were fully welded together (not especially neatly unfortunately) and the bearings pressed in. i was happy that every was lined up lovely and the two parts were pretty identical, which was the main thing. As ever, even though I’m a log way off producing “weld porn” style welds, I am always confident of the strength of TIG. I regularly practice on small parts, and even the shittiest looking weld never seems to break, even when I take the whole lot outside and smash it flat with a hammer. ‘Nuff said.

So now I needed to make the mounting pieces that would hold the above axle onto the end of the box section front member. These were essentially two pieces of 3mm flat bar, with three holes in each – one for the kingpin, and another two to bolt to the box section. I cut three pieces of bar to length and then used double sided tape to fix the all together dead flush. I then maked out the holes on the top one, and drilled through the lot using my pillar drill. Sorted.

Here you can see how they go together. The bolts are too long of course (correct ones here at time of writing) but that’s the general gist. Tighten the lot up and I’m good to go. It was at this point I realised I’d forgotten to weld the steering points onto the bearing carrier (for the track rods to fix to) but no matter – a bit more 3mm bar will sort that out in short order. THEN it will be finished…

The rear axle was next. As no steering was required this was a lot easier, but I thought I would try and make it difficult by building in some extra ground clearance. The axle bolts were located in metal bungs – essentially a 22mm dia piece of round bar, 25mm long, with an 8mm hole through the middle. These were welded into the ends of a length of box section.

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Here you can see the box section with a small hole drilled into each side. The insert was knocked into place, and then a small puddle of weld was put into each of the holes. This should stop the insert from de-inserting itself…

To add an extra inch of ground clearance at the back, this bar was now lined up and clamped to another identical piece of bar. Then, for 50mm on either end they were welded together. Then, the unwelded length of bar was cut out.

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This added the extra ground clearance, and because the lower selections were welded together as on long piece, I now know that the wheels are in line.

So there we go, a back axle ready to go – just needs bolting onto the chassis and then it’s merely the small issue of designing and making some brakes… Stay tuned, folks…

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