SPRINGS 



123 



Twist Test : Samples taken from any part of the bundle of wire must withstand 

 twisting seven revolutions forward and seven reverse, at a twisting speed not to exceed 

 25 r.p.m., for the number of times as given in the following table, and the ultimate 

 break must be clean and square. 



Length of wire between grips, 10 in. : 



Diameter of wire, in . . 



Minimum twisting 



cycles 



0.1055 



23 



0.1205 



20 



0.1250 



20 



0.1350 



18 



0.1483 



17 



0.1563 



16 



0.1620 



15 



0.1770 



14 



Length of wire between grips, 15 in. : 



Diameter of wire, in . . 



Minimum twisting 



cycles 



0.1875 



20 



0.1920 



19 



0.2070 

 18 



0.2188 

 17 



0.2253 

 16 



0.2437 

 15 



0.2500 

 15 



0.2625 

 14 



Length of wire between grips, 20 in. : 



Diameter of wire, in 



Minimum twisting cycles . 



0.2813 



18 



0.2830 



17 



0.3065 

 16 



0.3125 

 16 



0.3310 

 15 



0.3438 



14 



0.3625 

 14 



Length of wire between grips, 30 in. 



Diarneter of wire, in. 



Minimum twisting 



cycles 



0.3750 



20 



0.3938 



19 



0.4063 



18 



0.4305 



17 



0.4375 



17 



0.4615 



16 



0.4688 



16 



0.4900 



15 



0.500 



15 



0.5313 



14 



0.5625 



13 



4. Surface Conditions 



Upon etching with a hot solution of hydrochloric acid sufficiently to disclose 

 surface defects, no hairline cracks, seams, pits, gouges, die marks, or other imperfec- 

 tions shall be revealed. Decarburization must be held to a minimum. 



5. Limits of Variations in Diameter 



Wire diameter 0.162 in. and less — plus or minus 0.0015 in. 

 Wire diameter 0.1770 in. and over — plus or minus 0.002 in. 



6. Inspection, Rejections, and Replacements 



AU springs will be rigidly inspected at the plant as received. If more than a 

 total of 10 per cent of the springs on any one purchase order are made of steel that 

 fails to comply with the preceding specifications, or with the specifications on the 

 detail drawing, the entire lot will be rejected. All springs rejected at the plant wHl 

 be held at the seller's risk for a reasonable length of time, subject to his instructions, 

 and shall be replaced by the seller without further cost to the purchaser. 



