From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Manufacture of rivetless bonnets and the issues with using steel.
| Identifier | ExFiles\Box 102\6\ scan0117 | |
| Date | 18th June 1931 | |
| To Hs.{Lord Ernest Hives - Chair} from Ev.{Ivan Evernden - coachwork} c. Sg.{Arthur F. Sidgreaves - MD} E.{Mr Elliott - Chief Engineer} Bv. X5260 Ev{Ivan Evernden - coachwork}2/18.6.31. X.385 X.7260 X.5260 RE : RIVETLESS BONNETS. This is to confirm our conversation re the matter of rivetless bonnets by telephone yesterday. You say that countersunk rivets in alumeminium cannot be considered, and our experience endorses that conclusion. In connection with the steel bonnet we suggest that as you have no electric spot welding plant, the best way to get a steel bonnet welded up would be to send the pieces to some firm that does such work extensively, such as the Pressed Steel Company of Gt. Britain, at Cowley. STEEL BONNETS. It was agreed that you would proceed to build up a bonnet preferably for the 20/25 HP. having panels of 22 SWG. steel. The hinges to be of the same design as now but in some untarnishable steel, and the side ginge to be sheathed as now. In all cases in the place of rivets we suggest electric spot welding. The stiffeners are to be in steel as on N.2. series F2. You have a design for a flip-flap shutter in steel. We now make a few observations on steel bonnets. Rust will be their biggest drawback, both blistering of paint, but worst still red rust stains will be washed over the paintwork from the ends of the bonnet where chafing has occurred. So far we have been unable to make any use of the idea of making the hinges in the edge of the panels themselves. The hinges cannot be painted as opening and closing the bonnet cuts the paint off the sectors. We see that it might be possible to sheath the side hinge with a strip of brass or steel sweated on and subsequently chromium plated, but we cannot see a way of covering the top hinge on account of the way in which it opens. | ||