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 material for hexagon versus square headed bolts.
| Identifier | ExFiles\Box 148\5\ scan0179 | |
| Date | 8th July 1937 | |
| To E.{Mr Elliott - Chief Engineer} from G/Rb.{R. Bowen} G/Rb.{R. Bowen}8/M/W.9787. Hexagon Versus Square Headed Bolts. E.1/HP.8.7.37. Regarding your query concerning the relative costs of material for N.S. Bolts, the table below gives you the information you require, and is based on the standards laid down by our K.{Mr Kilner} lists. The prices per ton include drawing down to size from rough rolled bar and are those applicable from July 1st 1937. SQUARE Size of Bolt. Size of Bar Weight for 10 ft (lbs) Price per Ton (£ s d) Actual Cost. (£ s d) 2 BA. .300 3.061 81 7 7 2 2½ .250 .375 4.776 75. 0. 4 3 2½ .312 .500 8.496 63 5 2 4 9½ .375 .550 10.272 62 0 2 5 8 .500 .750 19.104 47 5 8 8 1 HEXAGON. Size of Bar. Wt for 10 ft Price per ton (£ s d) Actual Cost. (£ s d) .338 3.360 76 0 4 2 3½ .448 5.904 63 5 2 3 4 .525 8.112 63 5 2 4 7 .601 10.620 55 2 3 5 3 .820 19.776 48 5 8 8 6 Totals for 10 ft of each. £1 3 11½ £1 3 11½ So far as the labour element is concerned, we are still of the opinion that no reduction in time allowances would be obtained on account of a change from square to hexagon section. G/Rb.{R. Bowen} | ||