Edges* f Similarly, the sheared edges must be planed off to a 

 depth of inch, so as to remove all the sheared surface of 

 the metal, wherever reaming of punched holes is required. 



130. All parts of any tension or compression flange or 

 member must be of the same kind of steel, but webs of 

 plate girders and the tension members of all girders, plate 

 or lattice, may be made of low steel in connection with 

 compression members of medium steel. 



131. All splices must be of the same kind of steel as the 

 parts to be joined. 



Pilot Nuts. 132. Pilot nuts must be used during the erection to pro- 

 tect the threads of the pins. 



QUALITY OF MATERIAL. 



STEEL. 



133. All steel must be made by the Open Hearth process. 

 The phosphorus must not exceed 0.08 of one per cent, for 

 steel made by the acid method, or 0.04 for steel by the basic 

 method. 



134. The steel must be uniform in character for each 

 specified kind. The finished bars, plates and shapes must 

 be free from injurious seams or flaws, cracks on the faces or 

 corners, or other defects, and have a clean, smooth finish. 

 No work shall be put upon any steel at or near the blue 

 temperature or between that of boiling water and of ignition 

 of hard- wood sawdust. 



135. The tensile strength, elastic limit* and ductility shall 

 be determined by samples cut from the finished material 

 after rolling. The samples to be at least 12 inches long, 

 and to have a uniform sectional area not less than J square 

 inch. 



136. Material which is to be used without annealing or 

 further treatment is to be tested in the condition in which 

 it comes from the rolls. When material is to be annealed 



* For the purpose of these specifications, the Elastic Limit will be considered the least strain 

 producing a visible permanent elongation in a length of 8 inches, as shown by scribe marks of a 

 pair of finely pointed dividers. 



If the yield point or drop of the beam can be calibrated for any machine and its speed to 

 represent the elastic limit within 5 per cent., it may be used for general cases. Test reports must 

 state by which method the elastic limit was determined. 



