SPECIFICATIONS. 



TAI'.I.E IV. 



"Arbitration Bar" of the American Society for Testing Materials, which is round bar, ij in. in 

 (li.um'ter ami 15 in. long. The transverse test shall be made on a supported length of 12 in. with 

 the load at the middle. The minimum breaking load thus applied shall be 2,900 lb., with a 

 ck tk-ction of at least -fa in. before rupture. 



Workmanship, Inspection* and Painting. 21. All parts forming the structure shall be built 

 in accordance with approved drawings. The workmanship and finish shall be equal to the best 

 in modern shop practice. 



22. All material shall be thoroughly straightened in the shop, by methods which will not 

 injure it, before being laid off or worked in any way. 



23. The shearing shall be done neatly and accurately, and all portions of the work exposed 

 to view shall have a neat and uniform appearance. 



24. The size of each rivet, called for by the plans, shall be understood to mean the actual 

 size of the cold rivet before it is heated. 



25. All plates and shapes shall be shaped to the proper curve by cold rolling; heating or 

 hammering for straightening or curving will not be allowed. 



26. Plates to be scarfed may be heated to a cherry-red color, but not hot enough to ignite a 

 piece of dry wood when applied to it. Most careful attention shall be paid to all scarfing. 



27. All plates or shapes shall be punched before being bevel-sheared or planed for caulking. 



28. All screw threads shall make tight fits in the nuts and turnbuckles, and shall be United 

 States Standard, except for diameters greater than if in., when they shall have six threads per 

 inch. The dimensions of screws of various sizes shall be as follows: 



Diameter of screw ends I in. I f in. I J in. if and greater 



Number of threads per inch 8 7 7 6 



The minimum excess at the root of the thread over the body of the bar shall be 15 per cent. 



The shape of the thread shall be U. S. Standard. 



TABLE V. 

 STANDARD UPSETS FOR ROUND AND SQUARE BARS. 



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