ANNEALING.

In all cases where a steel piece in which the full strength is required has been partially heated or bent, the whole piece must be subsequently annealed. In pieces of secondary importance, where the bending is slight, said bending is to be made cold, and no annealing in such cases will be required. Crimped web-stiffeners will not require annealing.

All eye bars shall be carefully and uniformly annealed at a dark orange heat.

RIVETS.

Rivets when driven must completely fill the holes, have full heads concentric with the rivet-holes, and be machine-driven whenever practicable. The machine must be capable of retaining the applied pressure after the upsetting is completed.

The rivet-heads must be full and neatly finished, of approved hemispherical shape, in full contact with the surface, or be countersunk when so required, and of a uniform size for the same-sized rivets throughout the work; and they must pinch the connected pieces thoroughly together. Flattened heads may be used in certain places, if necessary for clearance. Except where shown otherwise on the drawings, all rivet diameters are to be seven eighths (7/8) of an inch. No loose or imperfect rivets will be allowed to remain in any part of the metal-work.

RIVET-HOLES.

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 distort the metal about the holes. The distance between the edge of any piece and the centre of a rivet-hole must never be less than one and a half (1 1/2) inches, excepting for lattice bars, small angles, and where especially shown otherwise on the Engineer's drawings; and, wherever practicable, this distance shall be at least two (2) diameters of the rivet.