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).
Brake drum material specifications, liner manufacturers, and developments in hydraulic dampers.
| Identifier | ExFiles\Box 181\M9\ img065 | |
| Date | 31th October 1931 | |
| -5- Silicon 2.00% to 2.20% Phosphorous .15% to .19% Manganese .75% to 1.00% Sulphur .09% Chromium .25% to .45% Brinnel:- Normal 300-220. Special Duty 230-260. Tensile strength 17-20 tons/sq.in. Transverse test 3200 lbs. Modulus of rupture 32-35 tons. This material is used for brake drums on many commercial vehicles including Morris Commercial, it is also used for Lagonda brake drums, it may possibly be of use to us in centrifugally cast form for brake drum liners. Laystalls exhibit hardened steel liners for brake drums but have had no experience with them in conjunction with aluminium. The Sheepbridge Stokes Centrifugal Castings Co. Ltd. exhibit brake drum liners centrifugally cast, but have had no experience with aluminium drums. This concern also exhibits 'Centricast' valve seats for cast iron cylinder heads (or blocks) which are pressed in, they claim freedom from erosion and they do not need screwing or in any other way fixing to the cylinder. They are experimenting with centrifugally cast aluminium bronze for the same purpose in aluminium engines but up to the present they are having trouble in securing seats in position. They say aluminium bronze centrifugally cast gives better results than phosphor bronze for this purpose. Their experiments to date have been devoted entirely to try to fix the valve seats by pressing in only; there is no reason why this material should not be screwed in as we do at present in aluminium engines. No other exhibitors are doing any work in this direction. Referring back to brakes there is a noticeable increase in the number of cars fitted with hydraulically operated brakes. This is a great saving in cost, avoiding the necessity for mechanical equalisation, operating rods etc. In the case of the Lanchester 15 - 18 HP. car this method is used in conjunction with a vacuum servo. Shock Dampers. Hydraulic dampers are now almost universal. Luvax are fitted to the majority of British cars and Delco to the Americans. The feature of dashboard control offered by Packard is bound to be adopted very widely in the near future. On the new small Mercedes model which has independent springing to all four wheels the front | ||