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).
Report from The Hoffmann Manufacturing Co. Ltd. on the examination of failed bearings from a Bentley gearbox.
| Identifier | ExFiles\Box 86\4\ scan0144 | |
| Date | 12th June 1937 | |
| HOFFMANN Registered Trade Mark BRANCHES: LONDON, BIRMINGHAM, MANCHESTER, LEEDS, GLASGOW. AGENTS IN PRINCIPAL COUNTRIES THROUGHOUT THE WORLD. TELEPHONE: 3151 (5 lines) TELEGRAMS: HOFFMANN CHELMSFORD CODES USED: A.B.C. 6TH EDITION, BENTLEY PHRASE, BENTLEY 2ND PHRASE, MARCONI AND WESTERN UNION 5 LETTER. THE HOFFMANN MANUFACTURING Co, LTD. BALL-AND-ROLLER-BEARINGS STEEL-BALLS-AND-ROLLERS CONTRACTORS TO THE ADMIRALTY, WAR OFFICE AND INDIA OFFICE. CHELMSFORD. June 12th. 1937. MESSRS. ROLLS-ROYCE LTD., DERBY. YOUR REF. Rm{William Robotham - Chief Engineer} 5/R.{Sir Henry Royce} IN YOUR REPLY PLEASE QUOTE OUR REF. CHS/AMB. FOR THE ATTENTION OF MR. GRYLLS. Dear Sirs, We thank you for your letter of the 2nd. instant and for the opportunity you have given us of examining the bearings from a Bentley gearbox. Of these, bearings Nos. 340, 335, 330, and N.1049 show no signs of failure, but the running tracks are indented due to the presence of metallic chips or other foreign matter. This would cause roughness and noisy running. The bearing No. N.1036 has failed by brittling of the track of the inner race. The outer race shows severe load all round and the outside diameter of the outer race has evidently been a very tight fit on its seating, the fit being so heavy, in fact, as to entirely eliminate the original diametric slackness and impose initial load. In our opinion this is the cause of failure, and from the appearance of the inner track, we think it occurred at a very early stage of its life. The brittling of the track removed the initial tightness and gave some running clearance, and subsequent to this the bearing has run without further breakdown. We have sent the bearing to our Birmingham Engineer, Mr. Brand, and have asked him to take an early opportunity of demonstrating to you the evidence on which the foregoing opinion is based. Yours faithfully, THE HOFFMANN MANUFACTURING CO. LTD. C. H.{Arthur M. Hanbury - Head Complaints} Smith Technical Manager. | ||