146 STEEL HIGHWAY BRIDGES. CHAP. III. 



143. Pin-Holes. Pin-holes shall be bored true to gages, smooth and straight; at right angles 

 to the axis of the member and parallel to each other, unless otherwise called for. The boring shall 

 be done after the member is riveted up. 



144. Variation in Pin-Holes. The distance center to center of pin-holes shall be correct 

 within i in., and the diameter of the holes not more than -fa in. larger than that of the pin, for 

 pins up to 5-in. diameter, and ^ in. for larger pins. 



145. Pins and Rollers. Pins and rollers shall be accurately turned to gages and shall be 

 straight and smooth and entirely free from flaws. 



146. Screw Threads. Screw threads shall make tight fits in the nuts and shall be U. S. 

 standard, except above the diameter of if in., when they shall be made with six threads per inch. 



147. Annealing. Steel, except in minor details, which has been partially heated, shall be 

 properly annealed. 



148. Steel Castings. All steel castings shall be annealed. 



149. Welds. Welds in steel will not be allowed. 



150. Bed Plates. Expansion bed plates shall be planed true and smooth. Cast wall plates 

 shall be planed too and bottom. The cut of the planing tool shall correspond with the direction 

 of expansion. 



151. Pilot Nuts. Pilot and driving nuts shall be furnished for each size of pin, in such 

 numbers as may be ordered. 



152. Field Rivets. Field rivets shall be furnished to the amount of 15 per cent plus ten 

 rivets in excess of the nominal number required for each size. 



153. Shipping Details. Pins, nuts, bolts, rivets and other small details shall be boxed or 

 crated. 



154. Weight. The weight of every piece and box shall be marked on it in plain figures. 



155. Finished Weight. Payment for pound price contracts shall be by scale weight. No 

 allowance over 2 per cent of the total weight of the structure as computed from the plans will be 

 allowed for excess weight. 



SHOP PAINTING. 



156. Cleaning. Steel work, before leaving the shop, shall be thoroughly cleaned and given 

 one good coating of pure linseed oil, or such paint as may be called for, well worked into all joints 

 and open spaces. 



157. Contact Surfaces. In riveted work, the surfaces coming in contact shall each be painted 

 before being riveted together. 



158. Inaccessible Surfaces. Pieces and parts which are not accessible for painting after 

 erection, including tops of stringers, eye-bar heads, ends of posts and chords, etc., shall have a 

 good coat of paint before leaving the shop. 



159. Condition of Surfaces. Painting shall be done only when the surface of the metal is 

 perfectly dry. It shall not be done in wet or freezing weather, unless protected under cover. 



160. Machine-finished Surfaces. Machine-finished surfaces shall be coated with white 

 lead and tallow before shipment or before being put out into the open air. 



INSPECTION AND TESTING AT THE SHOP AND MILL. 



161. Facilities for Shop Inspection. The manufacturer shall furnish all facilities for inspecting 

 and testing the weight and quality of workmanship at the shop where material is manufactured. 

 He shall furnish a suitable testing machine for testing full-sized members, if required. 



162. Starting Work in Shop. The purchaser shall be notified well in advance of the start 

 of the work in the shop, in order that he may have an inspector on hand to inspect material and 

 workmanship. 



163. Copies of Mill Orders. The purchaser shall be furnished complete copies of mill orders, 

 and no material shall be rolled, nor work done, before the purchaser has been notified where the 

 orders have been placed, so that he may arrange for the inspection. 



164. Facilities for Mill Inspection. The manufacturer shall furnish all facilities for inspecting 

 and testing the weight and quality of all material at the mill where it is manufactured. He shall 

 furnish a suitable testing machine for testing the specimens, as well as prepare the pieces for the 

 machine, free of cost. 



165. Access to Mills. When an inspector is furnished by the purchaser to inspect material 

 at the mills, he shall have full access, at all times, to all parts of mills where material to be inspected 

 by him is being manufactured. 



1 66. Access to Shop. When an inspector is furnished by the purchaser, he shall have full 

 access, at all times, to all parts of the shop where material under his inspection is being manu- 

 factured. 



