17 



tenths the width of the largest eye-bar attached to it. 

 The several members attaching to the pin shall be so packed 

 as to produce the least bending moment upon the pin, and 

 all vacant spaces must be filled with wrought filling rings. 



91. All bars with screw ends shall be upset at the ends, 

 so that the diameter at the bottom of the threads shall be 

 -j*j- inch larger than any part of the body of the bar. 



92. Where closed sleeve nuts are used on adjustable 

 members the effective length of thread shall be legibly 

 stamped at the screw ends of each bar. Adjustable 

 counters to be avoided where practicable. 



93. Screw threads must be of the United States standard, 

 except at the ends of the pins, and except for rods over 

 if in. diameter, where they shall be six threads to the 

 inch. 



94. In special cases, where floor beam hangers may be Hanger*, 

 permitted, they must be rigidly attached to the trusses and 



be so arranged as to stay the floor beams firmly against 

 rotation or end motion. ( 10.) 



95. Compression members shall be of steel, and of ap- comorcssior 

 proved forms. ( 35.) 



96. The pitch of rivets at the ends of compression mem- 

 bers shall not exceed four diameters of the rivets for a 

 length equal to twice the width of the member. 



97. The open sides of all compression members shall be Latticing, 

 stayed by batten plates at the ends and diagonal lattice- 

 work at intermediate points. The batten plates must be 

 placed as near the ends as practicable, and shall have a 

 length not less than the greatest width of the member or ij 

 times its least width. The size and spacing of the lattice 



bars shall be duly proportioned to the size of the member. 

 They must not be less in width than 2 inches for members 

 9 inches or less in width, nor 2j inches for members 12 109 

 inches in width, nor 2$ inches for members 15 to 12 inches 

 in width. Single lattice bars shall have a thickness not less 

 than -fa or double lattice bars connected by a rivet at the 

 ^ection not less than ^ of the distance between the 

 s connecting them to the members. They shall be in- 



