Yet another part started in the multitude of parts to be made. While plans are available for this via the R2 building groups around, the few I have seen for sale seem to either sell the centre round bit with no little triangle detail bits or outer lip, or the base from the round bit with detail triangle bits and not side wall or lip still. So my aim was to make an all in one power coupling that could be fitted easily from behind.
To start with the centre bit. This was actually quite hard to get right, as itís a very shallow angled cone, something that is quite hard to turn by hand on a lathe. Luckily I am quite versed in hand operated lathe work, so angles are a combination of turning both bed wheels at the same time but different rates, to get the desired angle.
Then with a bit more machining of the end, and a final sand with very fine sandpaper the centre piece was done.
Next it was time to do the ring part. I did think I could use a standard off the shelf bit of pipe, but none was quite the right size, they were either too big or too small. Luckily a bit of extractor tubing on my workshops had the correct outside diameter to be the right size of the inner diameter of the ring bit, so several strips of styrene sheet were cut and these stuck together round the bit of pipe to create the ring part.
I then started on the inner detail bits, and decided the best way to make them was straight from the scale plans to a piece of styrene sheet, then cut the segments I needed out. The ones off the bottom were not so difficult to do, as they were just sections of a ring, but the top corner segments were not all that big, and had sharp corners on them, which had to be right. In the end I cut two squares from styrene, then cut them in half, then carefully rounded the inner edge to the correct angle, as shown in the plans. Whenever working on something small like this more care is needed as its easier to damage or break one while working on it.
This bit was a real pain to make, not only is it angled, but itís a double angle on the face, the top section being a different angle to the bottom bit. Also to make it worst the side that attaches to the centre cone bit, is angled, as are both sides. To overcome the problem of having to make four identical ones, as one was proving hard enough, I put all my efforts into making one, and then moulded it to get the four I would use.
It was now time to start to assemble all the bits. I had made the ring part, and stuck it to another bit of styrene to form the base, and also made the top flange or lip part. As this is curved, and styrene doesnít bend and holds its shape well, just by physically bending it, I used several thinner layers and glued them together while holding them over the correct angled curve. This means when the glue has dried, the pieces of styrene are permanently held at the correct angle, making working with it much easier.
The ring and flange were then stuck together and a bit of model filler added to smooth out and joins, then the detail bits were stuck onto the flange.
With the cast centre sections now glued onto the centre part, and dried overnight, it was time to finish assembling it. at first I was just going to stick the bits in, but found it very hard to get the inner detail bits just where they needed to go at the bottom. To resolve this, I cut another very thin layer of styrene sheet and glued everything in place on the workbench, where they could be accurately placed, then stuck the complete centre section into the ring as a whole.
With this part now done, a mould was made so two could be cast. The mould had to be in tow parts, as the flange just would have got stuck trying to get it out a one part mould. Two part moulds tend to use more silicon, but makes life much easier when casting bits like this with a flange on.
Once cast and the resin fully cured overnight, a coat of primer, then aluminium effect paint is added to just finish if off nicely. Of course when done, the little segment bits need painting the colour of my droid, but that should be done quite easily with an airbrush.