90 



The actual readings of all micrometers are given in the tabulated statement 

 below : 



LOAD. 



Micrometer Readings at Different Loads. 







Total Deflection. 



5,000 

 10,000 

 15,000 

 20,000 

 25,000 

 30,000 

 .35,000 

 40.000 

 45,000 

 50,000 

 55,000 

 60,000 

 65,000 

 70,000 

 75.000 

 80,000 

 85,000 



.250 

 .275 

 .297 

 .310 

 .339 

 .365 

 .388 

 .412 

 .435 

 455 

 .485 

 .513 

 .546 

 .582 

 .627 

 .675 

 .782 

 .936 



.025 

 .022 

 .013 

 .229 

 .026 

 .023 

 .024 

 .023 

 .020 

 .030 

 .028 

 .03:3 

 .036 

 .045 

 .048 

 .107 

 .151 



.176 

 .200 

 .220 

 .2a3 

 .264 

 .288 

 .311 

 .334 

 .357 

 .380 

 .405 

 .434 

 .465 

 .498 

 .543 

 .585 

 .683 

 .816 



.024 

 .020 

 .013 

 .031 

 .024 

 .023 

 .023 

 .023 

 .02:3 

 .025 

 .029 

 .031 

 .033 

 .045 

 .042 

 .098 

 .1.33 



.145 

 .175 

 .199 

 .228 

 .265 

 .290 

 .315 

 .369 

 .370 

 .401 

 .438 

 .476 

 .522 

 .564 

 .633 

 .716 

 .839 

 1.068 



.030 

 .024 

 .029 

 .037 

 .025 

 .025 

 .054 

 .001 

 .031 

 .037 

 .038 

 .046 

 .042 

 .069 

 .083 

 .123 

 .229 



.027 

 .054 

 .067 

 .106 

 .142 

 .171 

 .200 

 .231 

 .263 

 .293 

 .330 

 .371 

 .420 

 .475 

 .5.32 

 .677 

 .879 



.025 

 .047 

 .060 

 .089 

 .115 

 .138 

 .162 

 .185 

 .205 

 .2:35 

 .263 

 .296 

 332 

 .377 

 425 

 .532 

 .686 



.024 

 .044 

 .057 

 .088 

 .112 

 .135 

 .158 

 .181 

 .204 

 .229 

 .258 

 .289 

 .322 

 .367 

 .409 

 ..507 

 .640 



.030 

 .054 

 .0S3 

 .120 

 .145 

 .170 

 .224 

 .225 

 .256 

 .293 

 .331 

 .377 

 .419 

 .488 

 .571 

 .694 

 .923 



The dimensions of the axle were such (Fig. 2) that when loaded to its elastic 

 limit, the maximum fiber stress at its center was 29,730; at 18 inches from the 

 center 22,100 pounds, and at the neck of the journal 20,600 pounds. 



The axle tested was designed for use under a freight car of 60,000 pounds 

 capacity, the car itself weighing about 20,000 pounds. Each of the four axles 

 under such a loaded car, therefore, must withstand a static load of 20,000 pounds, 

 which load would develop a maximum fiber stress in the center of the axle tested 

 of 10,810 pounds. In comparing these values with those obtained in the tests as 

 given in the preceding paragraph, it is important to remember that the stresses 

 to which car axles are subjected when in service arise from complicated condi- 

 tions, and that their value can not be determined from atatic conditions alone. 



The test specimen which was forged down from the crop end of the axle was 

 turned down in the center for a distance of 8.5 inches and tested under tension. 

 The results are as follows : 



Diameter in inches 1.875 



Area of cross section ' 2.755 



Total load, pounds 140,700. 



Ultimate strength, pounds, per stjuare inch 51,070. 



Elastic limit 30,000. 



Modulus of elasticity 29,671,000. 



