I've used these hinges to represent diesel loco bonnet hinges as well as things like shed door and tool box hinges. The hinges are very finely etched in 0.4 mm thick brass sheet and have very small tabs attaching them to the sheet.
Victorian Railway RT rail tractor H0, etched brass kit + BlackBug Mashima motor
CHATHAM KITS 'OO' GAUGE LBSCR STROUDLEY GOODS BRAKE VAN ETCHED BRASS KIT
Decent Models etched brass model kit part CR45U 45 ft U/Frame Frets Headstock
Pair of Hunslet Late Era Etched Brass Builders Plates for 16mm scale locomotive
Pair of Kerr Stuart Etched Brass Builders Plates for 16mm scale locomotive
Etched Brass Cranks, Levers, Linkage Components for Wagons, Locomotives etc