The length of a tie-plate shall never be less than its width, or one and one-half (1 1/2) times the least dimension of strut (unless it be close to a web diaphragm of the member, in which case it may be as short as twelve (12) inches), and seldom greater than one and one-half (1 1/2) times its width.

The thicknesses of lacing-bars shall never be less than one fiftieth (1/50) of the length between centres of the end rivets, measuring between inmost rivets in case that there be more than one rivet at each end. The smallest section for a lacing-bar shall be one and three quarter (1 3/4) inches by three eighths (3/8) of an inch, which size shall be used for channels under nine (9) inches deep; and the largest section shall be two and a half (2 1/2) inches by one-half (1/2) inch, which size shall be used for channels fifteen (15) inches deep. For intermediate sizes of channels, the sizes of lacing-bars shall be interpolated. For all built channels of greater depth than fifteen (15) inches, and for all cases where a lacing-bar would require a greater thickness than one-half (1/2) inch, angle lacing is to be used, the smallest section for same being 2" X 2 1/2" X 3/8", and the largest 2 1/2" X 3 1/2" X 3/8". For two (2) inch lacing-bars and two and a half (2 1/2) inch lacing angles, three-quarter (3/4) inch rivets are to be used; and for two and a half (2 1/2) inch lacing-bars and three (3) inch lacing-angles seven-eighths (7/8) inch rivets are to be adopted.

In general, the inclination of lacing-bars to axis of member shall be about sixty (60) degrees; but in members of minor importance and in tension-members the said inclination may be made slightly flatter.

Pin-plates shall be used at all pinholes in built members for the double purpose of reinforcing for the metal cut away and reducing the intensity of pressure on pin and bearing to or below the specified limit. They shall be of such size as to distribute properly, through the rivets, the pressure carried by such plates to both flanges and web of each segment of the member; and they shall extend at least six (6) inches within the tie-plates of said member, so as to provide for not less than two (2) transverse rows of rivets there.

When the pin ends of compression-members are cut away