These include King bolts or King rods, which hang from the apex of the roof, and all rods parallel to them which suspend the tie rod from the rafters.

In iron roofs all suspending rods except the King bolt or King rod are called Queen bolts or Queen rods.

These rods are generally formed with a fork at the upper end, so as to embrace the web of the principal rafter, to which they are secured by a bolt.

The lower ends of the rods pass through a hole in the tie rod, and terminate in a screw carrying a nut, by screwing up which the tie rod may be raised and the truss set up.

Struts should, unless they are very short, be of wrought iron in preference to cast iron, as the latter are clumsy, apt to get broken in transit, and to snap suddenly in the work.

For small roofs the struts are generally made of angle or T iron, or sometimes of two T irons riveted together so as to form Fig. 383.

Fig. 383a.

Fig. 385. a cross thus - or of two channel irons similarl united.

Fig. 384.

Very efficient struts are formed by flat or angle irons kept apart by distance pieces, varying in length so as to form a tapering beam. Such a strut with one distance piece for a small roof is shown in Figs. 396, 397, Plate IV., a longer one with three distance pieces in Fig. 437, Plate IX.