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 collan oil as a dressing for asbestos brake linings and the causes of brake squealing.
| Identifier | ExFiles\Box 26\4\ Scan279 | |
| Date | 19th February 1926 | |
| FERODO LIMITED. WIRES: "FRICTION, CHAPEL-EN-LE-FRITH". TELEPHONES: 19, 20 & 21 CHAPEL-EN-LE-FRITH (3 LINES). CODES: 5TH EDITION A.B.C. LIEBER'S. MARCONI INTERNATIONAL. WESTERN UNION FIVE LETTER EDS. Depots. LONDON 222, TOTTENHAM COURT ROAD, W.1. BIRMINGHAM 202, CORPORATION STREET. MANCHESTER 32, CATHEDRAL STREET. LIVERPOOL 1-3, BERRY STREET. GLASGOW 65, BOTHWELL STREET. BRISTOL 19, PARK STREET. BELFAST 158, NORTH STREET. LEEDS 25, HUNSLET ROAD. BRIGHTON 156A, WESTERN ROAD. MESSRS T. S. ARMSTRONG & CO LTD, NEWCASTLE ON TYNE, WORSWICK STREET, PILGRIM STREET. MESSRS HASLAM & STRETTON LTD, CARDIFF, 11, WINDSOR PLACE. MR A.{Mr Adams} J.{Mr Johnson W.M.} CRESWICK, SHEFFIELD, GATEFIELD. MESSRS F.{Mr Friese} W. HARRIS & CO, STOKE ON TRENT, MOORLAND ROAD, BURSLEM. MR SIDNEY HILL, COVENTRY, 1, QUEEN'S ROAD. NORTHERN MILL & MINE FURNISHING CO, CARLISLE, ANNETWELL STREET. Foreign Factories. FERODO AND ASBESTOS INC. U. S. A.{Mr Adams} NEW BRUNSWICK, NEW JERSEY. LA{L. A. Archer} SOCIETE ANONYME FRANCAISE DU FERODO, PARIS. 2, RUE DE CHATEAUDUN. DIE DEUTSCHE FERODO GESELLSCHAFT, BERLIN, MARIENDORF. KOPKEN & CO GROSSBEEREN STRASSE, 126. Reg'd Office & Works. SOVEREIGN MILLS, CHAPEL-EN-LE-FRITH, VIA STOCKPORT. PLEASE ADDRESS YOUR REPLY, DEPT. REF. FJF:DHL YOUR REF. Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}2/LG. February 19th, 1926. Messrs Rolls Royce, Limited, Experimental Department, DERBY. For the attention of Mr E.{Mr Elliott - Chief Engineer} W. Hives Dear Sirs: We received your very interesting letter and cutting in due course, and would have replied before this but for the fact that we know little or nothing of collan oil, although most engineers are familiar with its name, at least, in connection with a dressing for leather, and all the chemists with whom we are acquainted can give us no information; many have never heard of it - certainly no reference is contained in any work on Applied Chemistry. So far, we are advised that it comes from Norway, and is probably a mixed animal oil. We are obtaining samples, and by analysis shall know more about it, but we should say its effect will be just about on all-fours with Neatsfoot or other animal oil. Just where the advantage of Collan Oil comes in as a dressing for asbestos surface brake lining over a good-class hydrocarbon oil is difficult to say. We should rather prefer to recommend the latter. However, this is a little beyond the point in question. The only effect of lubricant in any form is to reduce the coefficient of friction at the contacting surfaces, since squealing, in our opinion, is due to the relatively high value of the coefficient in relation to the components of the shoe, which under certain conditions of the rubbing surfaces tend to jamb if from any cause the friction increases beyond a certain value. This servo action appears to us to be the prime cause of vibration, but whatever combination of factors start that vibration in shoes or drum there is no doubt that the latter vibrates and is acoustically well designed to amplify very greatly any high frequency vibrations communicated to it. There are many sorts of transmission murmurs from even the best rear-axle assembly, but it takes a steel disc wheel to shew them up, and whatever the prime cause of brake screeching, it is the generally comparatively thin steel drum which transmits the vibration to the surrounding air. In course of our | ||