JohnD Posted July 11, 2019 Report Share Posted July 11, 2019 Interesting post over on the Triumph Experience. A dedicated restorer has found that his 'bonnet iron' (UKspeak - hinge tube for bonnet) is a double tube, one inside the other! I presume for stiffness/strength. See: https://www.triumphexp.com/forum/spitfire-and-gt6-forum.8/dissecting-a-bonnet-iron.1630259/ He was concerned about the amount of rust between the two, which had holed at one point, and appears to have largely cut off the outer tube in sections, intending to weld it all back together (!!) when he's de-rusted it. But is this a known feature of the bonnet tube? Early, late? And which cars had them, all small chassis Triumphs with the forward tilting bonnet? Several owners on t'other side o't'Pond have found the same, by looking into the end of the bonnet tube. This is a newly discovered detail of how Triumph built thier cars, and needs investigation. Were all small chassis, forward tilting bonnet cars built this way, or was it certain models, certain times? Please will you have a look at your bonnet tube? Is it double or single walled? And report with the mark and model you examined? Then we'll know for sure! John Link to comment Share on other sites More sharing options...
eddyinfreehold Posted July 29, 2019 Report Share Posted July 29, 2019 This is my UK G Reg 1969 mk3 .... from what I can see it looks like a single tube and a seam is exposed in one place!! The car was extensively renovated well before I bought it so the part may be non original or even fabricated. I hope it helps though. Eddy Link to comment Share on other sites More sharing options...
JohnD Posted July 30, 2019 Author Report Share Posted July 30, 2019 Eddy, That I didn't comment on this before reveals my own ignorance of Spitfire/GT6 construction. The Herald/Vitesse version is one long tube, that supports the centre of the bonnet and the hinges on which it pivots. The Spitfire/GT6 has a central tube and two seperate hinge tubes, all fixed to the wheel arch. The OP over on the Spitfire Experience was referring to the hinge pieces, not the cross bar that you have shown. John Link to comment Share on other sites More sharing options...
Badwolf Posted July 31, 2019 Report Share Posted July 31, 2019 John - I have removed one of the bonnet support tubes from my MkIV Spitfire during the restoration, and following your post along with the triumphexp.com thread, had a look at it more closely. It does look like there is a double tube at the hinge end (front) but at the other, open end (back), it only appears to be a single skin. Does this help in any way. There does not appear to be any rust on mine at the moment but I am in the process of stripping the paint so will keep everyone informed. I was planning to POR15 the tube when cleaned up and then flood the inside with Dinitrol cavity wax before refitting which should, hopefully deal with any internal rust for the rest of the car's stay with me. I really don't relish the though of carving it up to look inside!! Link to comment Share on other sites More sharing options...
JohnD Posted July 31, 2019 Author Report Share Posted July 31, 2019 There you go, confirmation of this detail. You should ask the OP on The Triumph Exoerince hiow far back the doubling goes. That would be anothet facet of this to work out!. He was concerned by rust between the two layers, but I fear that any paint or anti-corrosion layer wil make reassembly impossible, and won't be accessed by your Dinitrol. John Link to comment Share on other sites More sharing options...
Badwolf Posted July 31, 2019 Report Share Posted July 31, 2019 John - It doesn't really worry me too much as there is are no signs of holes in the outer tube. I only noticed the double tube by looking down the end. As for rust prevention, apart from the water used to clean off the paint stripper etc I am not really worried about it. I will dry off the internal tube as best and poor in a let down solution of dinitrol so that it runs easily into the tube, slosh it around, drain it off and let the solvent evaporate. That should be as good a rust proof as it needs for the next few years. Link to comment Share on other sites More sharing options...
eddyinfreehold Posted August 1, 2019 Report Share Posted August 1, 2019 Oops. I should have looked more closely at the postings from the other site. When I am sorted with these carburettors (see Fuel System) I will have a look and repost. Yes I get the Spitfire hinges have their own separate rods though not as easy to inspect or photograph. Link to comment Share on other sites More sharing options...
PeteH Posted August 26, 2019 Report Share Posted August 26, 2019 Hi Short of getting into the "head" of the designer. May I proselytise?. In the 60`s there was a tendency for Motorcycle makers to use Reynolds tubing. This came as a high strength thin-wall tubing, IF Triumph in their wisdom thought that this would be a good material to use for this (high stress) situation, they may well have decided that as a "belt and braces" approach to construct the Item in this fashion, to increase stiffness in the critical area`s around the bends. Link to comment Share on other sites More sharing options...
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