diameters from the edge of a plate, and, whenever practicable, this distance is to be increased to two (2) diameters.

The rivets when driven must completely fill the holes.

The rivet-heads must in general be round; and they must be of uniform size for the same-sized rivets throughout the work. They must be neatly made and concentric with the rivet-holes, and must thoroughly pinch the connected pieces together.

Rivets with flat heads shall be preferred to countersunk rivets; the height or thickness of the flat head shall be three eighths (3/8) of an inch.

Rivets shall not be countersunk in plates less than seven sixteenths (7/16) of an inch in thickness.

Flanges of stringers and girders carrying the vertical load from the ties shall have their rivets spaced uniformly from end to end, and at the minimmum distance employed.

Whenever possible, all rivets shall be machine-driven, and the machines must be capable of retaining the applied pressure until after the upsetting is completed.

Field-riveting must be done with a button sett; the heads of the rivets must be hemispherical, and no rough edges must be left.

All rivets in splice or tension joints are to be arranged symmetrically so that each half of any tension-member or splice-plate shall have the same uncut area on each side of its centre line.

No rivet, excepting those in shoe-plates and roller or bed plates, is to have a less diameter than the thickness of the thickest plate through which it passes.

The effective diameter of any rivet shall be assumed the same as its diameter before driving; but, in making deductions for rivet-holes in tension-members, the diameter of the holes shall be assumed one eighth (1/8) of an inch larger than that of the rivet. In the effective area of riveted members, pin, bolt, and rivet holes shall be counted out for tension, and bolt and pin holes shall be counted out for compression.