j 3 o THE IMPROVEMENT OF RIVERS. 



edges. Rivet-holes must be accurately spaced; the use of drift-pins will be allowed 

 only for bringing together the several parts forming a member, and they must not be 

 driven with such force as to disturb the metal about the holes. 



Built members must, when finished, be true and free from twists, kinks, buckles, 

 or open joints between the component pieces. Pin-holes must be accurately bored at 

 right angles to the axis of the piece, and where a pin passes through two or more plates, 

 the holes must be truly opposite after fitting up. 



In all cases where a steel piece in which the full strength is required has been par- 

 tially heated the whole piece must be subsequently annealed. All bends in steel must 

 be made cold, or if the degree of curvature is so great as to require heating, the whole 

 piece must be subsequently annealed. Upset ends must be forged out of the solid bar, 

 and not welded on. All pieces which work or connect with other pieces must be 

 accurately assembled before shipment. Threads and other parts liable to injury during 

 transportation must be properly protected. 



58. Alterations. If, during the progress of the work, it is found advisable by the 

 United States to make any minor alterations, these must be made by the contractor 

 without charge to the United States. If any alterations be deemed advisable which 

 materially increase or diminish the cost of the work, the price for such alterations must 

 be agreed upon in writing and approved by proper authority before the change is made, 

 or nothing in addition to the contract price will be allowed. 



Note. If the lock gates are to be of steel, the following specifications for them 

 may be used, clauses as to material, inspection, etc., being covered by the preceding 

 paragraphs: 



Lock-gates. There will be two pairs of steel lock-gates, built as shown on the 

 drawings. 



The contractor will be required to make whatever shop drawings are required, and 

 as soon as these are made shall furnish, free of charge, two blue-print copies of each to 

 the Engineer. 



The gates shall be riveted up and shipped in such sections as will reduce the num- 

 ber of field-joints to a minimum. Each gate must be fitted together complete before 

 shipment, and all imperfections of workmanship remedied. 



The framing and riveting of the gates must be done to the satisfaction of the Engi- 

 neer, and must be such that each pair, when closed, will make a water-tight barrier 

 across the lock, allowing no leak^through the metal work, or between the woodwork 

 and the metal, or between the woodwork and its bearings. The gates will be tested 

 at the normal level of both pools as soon as practicable after the completion of the dam, 

 and any leaks or other defects must be made good by the contractor at his own expense. 



The timber cushions and fenders of the lock-gates must be of white oak, sound, 

 clear and free from all defects, and accurately dressed to the dimensions shown.* They 

 must receive two coats of linseed oil as soon as dressed, and the first coat must be thor- 

 oughly dry before the second is applied. 



