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).
Specification sheet for 'Safeguard' brake lining, detailing its types and a table of friction coefficients.
| Identifier | ExFiles\Box 141\3\ scan0143 | |
| Date | 14th February 1933 guessed | |
| "SAFEGUARD" BRAKE LINING. This is the standard type of Brake Lining with black finish supplied either as Die Pressed Liners hydraulically moulded to radius or in rolls of 50 feet or more as required. Die Pressed Liners of any dimensions can be supplied, and the material in rolls is supplied from a width of 1" up to 18", the thickness varying from ⅛" to 1". Only the finest grades of asbestos are used in the manufacture of "SAFEGUARD" Linings, and it is spun either on brass wire, as is customary, or without the wire. In the former case the material is referred to as "Metallic" or "Reinforced" or "Bonded", all these terms being synonymous, and when woven without the wire the Lining is referred to as "Non-metallic". In the form of moulded segments for Morris, Ford and Austin vehicles sets of liners are supplied in boxes, drilled and including rivets for fixing the lining to the brake shoes. The following Technical Data will be found useful for comparison and to designers. "SAFEGUARD" METALLIC LINING. VALUES OF CO-EFFICIENT OF FRICTION AT VARIOUS SPEEDS FROM 1000 to 4000 Ft./Min. WITH CAST IRON DRUM. Constant Pressure on Lining = 13.96 lbs/sq.ins. Temperature = 80 - 90° C. Speed Ft./min. Co-efficient of Friction. 4450 .400 4260 .400 4050 .408 3800 .404 3510 .404 3230 .433 3010 .433 2760 .421 2480 .430 2280 .433 2000 .435 1800 .430 1500 .440 1000 .450 | ||