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).
The tensile tests of four bolts fitted with 'Perfloc' nuts, received from The Engineering Improvement Co Ltd.
| Identifier | ExFiles\Box 77\5\ scan0220 | |
| Date | 30th March 1912 | |
| 14, Old Queen Street Westminster, S.W. 30th day of March 1912 Report on Tensile Tests of Four Bolts fitted with "Perfloc" nuts Received from The Engineering Improvement Co Ltd Received 22nd March Tested 22nd March | Test Number | Marks | Dimensions of Bolt | Limit of Elasticity (Yield Point) | Breaking Load | Ratio of Limit to Break | Extension on whole length at fracture per cent | Reduction of Area at fracture per cent | Works of fracture Inch. tons per Cubic Inch (calculated) | Remarks | |---|---|---|---|---|---|---|---|---|---| | | | Breadth Inches, Thickness Inches, Area Sq Inches | Pounds, Tons per Sq. Inch | Pounds, Tons per Sq. Inch | | | | | | | 35111 | None (¾" Steel Bolt bright all over as received) | 0.747 diam, 0.4383. At bottom of thread 0.611 diam, 0.2932 | 53,330, 23.81 | 84,320, 37.65 | 0.632 | on 2" 4.0 (Not including fracture) | - | - | At 5.64 tons, nut taken out of machine, nut uninjured. Bolt broke just at face of nut. fracture finely crystalline, nut uninjured. | | 35112 | None (¾" Steel Bolt turned down to bottom of thread) | 0.611 diam, 0.2932 | 41,250, 18.42 | 70,290, 31.39 | 0.587 | on 2" 36.0 (including fracture) | - | - | At 5.14 tons, nut taken out of machine, nut uninjured. At 5.64 tons. do. Bolt broke in parallel part. fracture granular, silky at edge. nut uninjured. | | 35114 | None (Ordinary 1" iron bolt skimmed up) | 1.032 diam, 0.8365. At bottom of thread 0.829 diam, 0.5398 | 55,940, 24.97 | 59,750, 26.68 | 0.936 | on 5" 0.8 (Not including fracture) | - | - | At 10.2 tons, nut taken out of machine and tried for tightness by screwing on - found unaltered. Bolt broke just inside nut. fracture fibrous. nut uninjured. | | 35113 | None (Ordinary 1" iron bolt turned down to bottom of thread) | 0.839 diam, 0.5529 | 41,070, 18.34 | 54,350, 24.27 | 0.756 | on 5" 10.8 (not including fracture) | - | - | At 9.2 tons, nut taken out of machine. nut uninjured. Bolt broke suddenly at head. fracture coarsely crystalline. nut uninjured. | (Signed) Bursall & Monkhouse. | ||