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).
Cost comparison of various brake drum assemblies.
| Identifier | ExFiles\Box 120\1\ scan0068 | |
| Date | 3rd December 1931 | |
| 3.12.31. COMPARISON OF P.II. BRAKE DRUM COSTS | | Material Cost | Labour Cost | TOTAL | |---|---|---|---| | Cast Iron Ribbed Brake Drum as supplied by Lake and Elliott | 16. 0 | 15. 6 | | | End Plate | 10. 0 | 12. 6 | | | Studs(12 off) | - | 1. 0 | | | Total | £1. 6. 0 | £1. 9. 0 | £2. 15. 0 | | P. II. type pressed drum | 18. 3 | 16. 3 | | | Damping Springs | 1. 6 | - | | | Sectors(4 off) | 1. 0 | - | | | Total | £1. 0. 9 | 16. 3 | £1. 17. 0 | | P. I. Ribbed type | £2. 10. 0 | £1. 10. 0 | £4. 0. 0 | The cost of the Lake and Elliott Brake Drum complete with end plate and studs is 50% greater than the present P.II. pressed drum(including damper sectors and Springs). The cost of Lake and Elliott type compared with P.I. is 30% less. | ||