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).
Tensile and vibration tests of bolts fitted with 'Perfloc' nuts.
Identifier | ExFiles\Box 77\5\ scan0219 | |
Date | 19th April 1912 | |
14 Old Queen Street, Westminster, S.W. 19th day of April 1912. Report on Tensile Tests of Two 1" Bolts fitted with 'Perfloc' nuts and Vibration Test on one 3/4" 'Perfloc' nut. Received from the Engineering Improvement Co Ld. Received 1st April. Tested 19th April. | Test Number. | Marks | Dimensions of Bolt (Breadth Inches, Thickness Inches, Area Sq. Inches) | Limit of Elasticity (Yield Point) (Pounds, Tons Per Sq. inch) | Breaking Load (Pounds, Tons Per Sq. inch) | Ratio of Limit to Break | Extension on whole length of | Reduction of Area at Fracture per cent. | Work of fracture in Inch tons per Cubic Inch (calculated) | Remarks. | |---|---|---|---|---|---|---|---|---|---| | 35130 | None (1" Steel Bolt bright all over as received) | 1.002 diam; 0.7885 At bottom of thread 0.845 diam; 0.5608 | 39,140, 17.48 | 61,650, 27.53 | 0.635 | 4.0 (not including fracture) | - | - | Bolt broke three threads distant from outside of nut; fracture granular. Nut unaffected. | | 35131 | None (1" Steel Bolt turned down to bottom of thread) | 0.845 diam; 0.5608 | 39,140, 17.48 | 56,220, 25.10 | 0.696 | 43.7 (including fracture) | 68.14 | - | Bolt broke in parallel part; fracture finely granular, silky at edge; cup fracture. Nut unaffected. | | 35155 | None | Four plates 7/8", 1/4", 3/8", and 3/8" thick respectively, were bolted together by two 3/4" bolts, 6" apart. One bolt had 'Perfloc' nut, the other an ordinary nut, fairly tight fit. Both nuts were tightened hard up so that spring was taken out of plates. 30 blows with a 10.lb hammer made no difference. Both nuts were then slacked back to allow some spring in plates, and a plain nut jammed down on ordinary nut to lock it. The ordinary nut was tightened up twice during 35 blows, made in order to take out bend of plates. Finally a further 35 blows slackened the ordinary nut, but did not affect the 'Perfloc' nut in any way. | | | | | | | | The Secretary, The Engineering Improvement Co Ld, 39, St James' Street, S.W. (Signed) Burstall & Monkhouse. | ||