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).
Comparative testing of forged steel versus cast iron brake drums, including issues with squeaking and cracking.
| Identifier | WestWitteringFiles\W\September1931-November1931\ Scan083 | |
| Date | 14th November 1931 | |
| To R.{Sir Henry Royce} From Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} c. to SG.{Arthur F. Sidgreaves - MD} Wor.{Arthur Wormald - General Works Manager} c. to E.{Mr Elliott - Chief Engineer} Da.{Bernard Day - Chassis Design} c. to By.{R.W. Bailey - Chief Engineer} Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}3/WJ.14.11.31. X4612. Re. Brake Drums. With reference to R.1/W.9.11.31. We have made and tested brake drums in forged steel to scheme M.S.3177. Whilst there is nothing really unsatisfactory in the behaviour of these drums, we found that their tendency to squeak was greater than similar drums in cast iron. Furthermore, the cast iron drums developed a particularly nice polish under working conditions. In view of these facts and the fact that the cast iron is likely to be less expensive than the forged drums, we carried out some endurance tests and discovered that the surface of the cast iron developed minute cracks, producing a crazy paving effect on the surface. By getting into touch with the commercial vehicle suppliers we found that a cast iron brake drum was produced by Messrs. Lake & Elliott which was free from such defects and further tests proved that their claims could be substantiated as the drums behaved remarkably well and the cracking trouble was completely overcome. Ribbed rear drums would have been run on the last 10,000 miles test, had not it been decided to get some mileage on the stiffer standard drum which has recently gone into production. With regard to the front ribbed drums, these have also been made and tested in steel. We attach a tabulated weight list of various drums. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||