The pricing, design alterations, and testing of Woodhead road springs for the Wraith model.
| Identifier | ExFiles\Box 9\5\ 05-page096 | |
| Date | 26th June 1937 | |
| Sg. {Arthur F. Sidgreaves - MD} from Rm {William Robotham - Chief Engineer} /Les. Re. c. S. c. REC. c. Hy. {Tom Haldenby - Plant Engineer} c. Roy. {Mr H. Royce - Buyer} c. Da. {Bernard Day - Chassis Design} 646 Rs {Sir Henry Royce's Secretary} /Les.2/H.26.6.37. WOODHEAD ROAD SPRINGS FOR WRAITH. The prices per spring for production quantities are:- Firth ........ £4.7.6. Woodhead ...... 1.19.6. The following alterations from the Firth's article have been made in order to reduce the price of the Woodhead springs:- (1). No cadmium plating. (2). Plates have minimum grinding in order to reduce friction and retain oil supply, but the decarburised surfaces are not removed. (3). Drawn taper points instead of ground points. (4). Simplified lubrication system. The following time has been run on the Wraith bumper chassis with Woodhead springs using 3" cams. 1. 4 hours 50 mins. } Fractures at 2. 9 " } small eye. 3. 32 " 15 mins. } Fractures at 3rd 4. 42 " 35 " } plate oil holes. Springs 1 and 2 failed owing to lack of metal thickness round the eyes, due to machining the bores of the eyes. Firths plates are produced from material a gauge thicker than the final plates, but the full thickness is kept for the eyes. As the Americans do not machine eyes, all further Woodhead springs have been supplied with unmachined eyes. We do not think that springs 3 and 4 would fail under road conditions. The average life of our standard rear spring on the bumper is about 40 hours with 3" cams. Our rear springs never fail on the road. | ||
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).