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).
Letter from Ferodo Limited discussing the high-temperature performance of brake linings and potential drum scoring.
| Identifier | ExFiles\Box 141\1\ scan0033 | |
| Date | 23th April 1935 | |
| All Communications to be addressed to the Company. X1180 FERODO LIMITED TELEPHONE: 19 CHAPEL-EN-LE-FRITH (4 LINES) TELEGRAMS: FRICTION, PHONE, CHAPEL-EN-LE-FRITH. FERODO BRAKE & CLUTCH LININGS CHAPEL-EN-LE-FRITH, STOCKPORT, ENGLAND. CODES: WESTERN UNION FIVE LETTER EDITION, BENTLEYS COMPLETE & 2ND PHRASE, MARCONI INTERNATIONAL, LIEBER'S CODE, LIEBERS LATEST CODE, A.B.C. 5TH & 6TH EDITIONS. 23rd April 1935 YOUR REF. Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls}18/KW OUR REF. JNL/KM. Depots:- LONDON 222, TENHAM COURT RD W.1. ABERDEEN 26, GUILD STREET. BELFAST 8, 10 & 12, MONTGOMERY ST BIRMINGHAM 198, CORPORATION ST BRIGHTON 84, QUEEN'S ROAD. BRISTOL 118, VICTORIA STREET. CARDIFF 39, CHARLES ST DUBLIN 120, UPPER ABBEY ST GLASGOW WATERLOO ST LEEDS 25, HUNSLET RD LIVERPOOL 1-3, BERRY STREET. MANCHESTER 32, CATHEDRAL ST NEWCASTLE-ON-TYNE WORSWICK CHAMBERS. 10, WORSWICK ST OFF PILGRIM ST G.H.Grylls Esq., Messrs. Rolls-Royce Ltd., DERBY. Dear Mr. Grylls, I must apologize for the delay in answering your letter of April 15th concerning the BZ linings on your Girling brake test. You ask what temperature would be required to produce the melting of our zinc alloy wire. Pure zinc, of course, melts at 419°C. and the melting point of our alloy wire is little over 400°C i.e. about 770°F.{Mr Friese} You may, therefore, safely conclude that to produce beads of molten zinc down the side of the lining i.e. at an appreciable distance from the rubbing surface, the temperature of the rubbing surface may have been well in excess of this 770°F.{Mr Friese} I am surprised to note that the drums are scored. Are you sure that this is scoring, or might it possibly be the adhesion of molten zinc to the drum ? Temperatures of the order you have experienced could be produced experimentally by us here. In fact, only a fortnight ago we determined the coefficient of friction of Ferodo BZ at 750°F as being .27. I am very much afraid that no known organic binder will withstand temperatures of this order, and would point out that asbestos itself begins to lose its fibrous characteristic and, consequently, its fibre strength, at 420°C. We are at this moment engaged on research having for its basis not the old ideal of having wonderfully prolonged life at 550°F but to produce an organic binder at such a high destructive distillation point as will enable it to withstand 700°F.{Mr Friese} An immediate result is hardly to be hoped for, and I am at a loss to know what next to suggest to you. I think probably the best step will be to determine the wear values of all our materials at 700°F, and to submit to you for your test a further set of whichever material turns out best on ours. This I will put in hand straight away, and will advise the result within the next week or so. Yours very truly, FERODO LIMITED CHIEF CHEMIST | ||