A chap I know is rebuilding a twenties Sunbeam; he is emphatic that the original damper discs should be made of wood such as beech. Andre Hartford car suspension dampers for example first used wood .....see Wikipedia etc.
Thoughts please.
Vic
From a practical viewpoint, though admittedly untraditional, hardboard seems to work very well I've used it for some years on the rear suspension of my Moto Guzzi.