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 estimation and analysis for a Smith Crankshaft, comparing versions with and without integral balance weights.
| Identifier | ExFiles\Box 8\5\ 05-page65 | |
| Date | 17th June 1919 | |
| To Messrs. From Mr/Sedl. C. B. C. S. H.{Arthur M. Hanbury - Head Complaints} S. G.{Mr Griffiths - Chief Accountant / Mr Gnapp} Og/Sg.{Arthur F. Sidgreaves - MD} G.{Mr Griffiths - Chief Accountant / Mr Gnapp} Dr. H/dms. S. H/axdl. HS{Lord Ernest Hives - Chair}/Sedl.1/HWH.17.6.19. SMITH CRANKSHAFT (Ex.9121). The following are estimations of the cost analysis on the above from inside and outside information. (1) The tool cost for forging the crank with integral balance weights is £600 as against £300 for the present type of crank without balance weights. (2) In V.S.M. the crank forging cost with integral balance weights is £3.15.0d. as against £4.5.0d. without the balance weights, or an increase of £1.10.0d. (3) The present loose balance weights, their material and (labour 200%) cost is approximately £2.15.0d. (4) The increased machining necessary with integral weights as against the crank without loose balance weight is estimated at 10/-d.{John DeLooze - Company Secretary} (labour 200%). The net reduction, therefore, in making integral weight shaft (factory cost) is - £2.15.0d. - £1.10.0d. - 10/-d.{John DeLooze - Company Secretary} = 15 shillings. In view of an extra £300 tool cost, 400 chassis would have to be made before any saving resulted. The above applies to a machined all over job. | ||