The scissors truss is shown in Fig. 242. It has no tie-beam and, therefore, it will exert considerable thrust on the walls of the building, which thrust must be taken care of by buttresses built on the outside of the walls. This is perhaps the most simple form of truss which can be used when an open timber truss is required.

Fig. 242. Design of a Scissors Truss

Fig. 242. Design of a Scissors Truss.

All the parts are of wood. If desired, an iron tie rod may be inserted between the two wall bearings of the truss, so as to eliminate the thrust on the walls, and this rod need not detract seriously from the appearance of the open timber work.