Wishbones - last of the steel era?

[MDCutting]

It's been a few weeks since my last post, but here's something that interests me. I've looked to see if anyone had posted a similar question and I don't it it's been raised before.

Whilst some categories still require fabricated steel wishbone construction, F1 moved on many years ago. Sometime around the '90s teams started using alternatives like wire eroded ti tubes, carbon wrapping and finally carbon tubes.

So here are some questions:

Does anyone know who was the last to use steel wishbone construction in F1?

What size aero tubes were typical towards the end of the era?

Who was first to use alternative materials?

In my time on F3 and LMP cars everything was definitely steel! Interestingly I noticed that Dallara F3 used tubes made from sheet welded together at the leading and trailing edge in a sort of flat "cat eye" section, without a directional shape, rather than aerofoil section which we used on our own cars. I suspect that we were using bearings that were larger despite the reduced loads on the F3 because we'd expect to use them for longer before replacement. As for tube size variation I don't remember if we used larger tube on lower and upper, pushrod size, etc. I do know we used aero tubes on the track rods and I've definitely seen F1 cars which used round track rods, which I found a little surprising.

Thoughts please!

[MDCutting]

Correction - my !memory definitely suggests we used smaller tube on at least top front, but it's been a while since I worked on 'em!

[peebee2]

Lotus/Caterham, Manor and Hispania all used steel when they joined as I recall.

[MDCutting]

That's interesting peebee, thanks! During the period when I worked at RTN (after TOM'S GB had changed over) we did some machining work on carbon tubes and end fittings for Super Aguri, which must have been around 2006. Caterham took over the Hingham site after we closed down and hence were definitely later!