I was sitting there in the evening playing with a stove on my workbench, thinking vaguely about the leg stability problem, when I actually SAW what I was looking at. That is, I actually looked closely at what the legs were really doing - and it was not at all what I had been assuming. I went to bed thinking about what I had seen, and in the morning I shot out to the workshop to make some replacement parts.
To cut a long story very short, the replacement parts made the standard tripod legs much stronger and more stable. The whole idea of a centre support is fine, but if the tripod is stable enough it is not needed for a little stove like this.
A longer story is that I had been slowly upgrading the legs from a quite different titanium version which combined the tripod with the pot supports. There are some photos of these in Part 2. But I had not gone the whole distance.
The new legs look like this. Well, OK, you may not even see any difference at first, except that the outer end of each leg now has a stylish tilt to it. The critical difference is at the pivot, where the rather small 14 mm shim washers which I had been using have all been replaced with much larger 22 mm Ti washers and brass shim washers. This has made a huge difference. (Anyone want a large supply of brass shim washers 14 mm diameter?)
There is one other small change in the leg profile: the small tab at the outer corner. This merits an explanation too. I machine each set of three legs together. That's a bit slow, but it makes for a much nicer set when they are folded together. The trouble was when the legs were all folded together they were packed really close together, and it was hard to separate them out. You could be sitting there at -20 C trying to set the stove up with gloves on and be cursing me for making the legs so hard to open. Not good enough.
The tabs on the two outside legs in the set are given a slight bend outwards, while the middle leg has a straight tab. Now it is easy to separate the legs. I should have forseen this as well, but I didn't.
The older tripod legs have been withdrawn and scrapped. The centre-support legs have also been withdrawn, although if anyone really wants them I can supply them from the existing stock. All stoves have been upgraded to the new improved legs.