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 The Hoffmann Manufacturing Co. Ltd. discussing bearing assembly specifications and limits.
| Identifier | ExFiles\Box 153\2\ scan0295 | |
| Date | 20th April 1937 | |
| [Handwritten: 1300] [Handwritten: FJH {Fred J. Hardy - Chief Dev. Engineer} ] BRANCHES: LONDON, BIRMINGHAM, MANCHESTER, LEEDS, GLASGOW. AGENTS IN PRINCIPAL COUNTRIES THROUGHOUT THE WORLD. HOFFMANN Registered Trade Mark BALL AND ROLLER BEARINGS STEEL BALLS AND ROLLERS THE HOFFMANN MANUFACTURING Co., LTD. — CONTRACTORS TO THE ADMIRALTY, WAR OFFICE AND INDIA OFFICE. — TELEPHONE: 3151 (5 LINES) TELEGRAMS: HOFFMANN, CHELMSFORD CODES USED: A.B.C. 5TH EDITION, BENTLEY PHRASE BENTLEY 2ND PHRASE, MARCONI AND WESTERN UNION 5 LETTER. MESSRS. ROLLS-ROYCE LTD., DERBY. CHELMSFORD. 20th April 1937 YOUR REF. Rm {William Robotham - Chief Engineer} /FJH {Fred J. Hardy - Chief Dev. Engineer} /14/AP IN YOUR REPLY PLEASE QUOTE OUR REF. JHW/BK {A. Birkett - Commercial Manager} DO.98919A Dear Sirs, We thank you for your letter of the 15th April reference as above and blue print. Regarding the F.61471 Assembly we note that this gives an overall assembled width of 1.232 ± .003" whereas the overall resulting from your detail limits is 1.2281 to 1.2416 and this could not be corrected except by facing the inner race out of limit. Your limits also allow a variation of .007 in the protrusion of the inner race from one side to the other. We would ask your consideration of the suggested method of limiting shown on the enclosed drawing No.41-473V Section 182. This would give the assembled width you ask and would keep the protrusion on two sides within a variation of .002". It would, of course, be necessary to delete the limit on the width of the inner race and the .354 dimension to the centre of the outer track. We would also suggest a small radius in the bore of the inner race and if you can accommodate we would prefer plus .0002 to minus .0003 limit on this bore. Similar remarks would apply to the FW.905 and FW.910 on which the limits on the track centres must be varied to suit the endways adjustment. We are looking into our costs for the smaller rollers and shall forward our quotation to you as soon as ever possible. Meanwhile, assuring you of our best attention at all times, we remain, Yours faithfully, THE HOFFMANN MANUFACTURING CO.LTD., P.S. Our Technical Manager Mr. C. H. {Arthur M. Hanbury - Head Complaints} Smith will discuss this matter with you during his visit to-morrow. Enc. Drg. No.41-473V Section 182. | ||