The middle posts are slightly larger in section, as they have to carry the cross rail supporting the swing; a good size for these is 6-in. diameter at the base by 10 ft. or 12 ft. high. The outer posts may be 4¾-in. to 5-in. diameter at the base. The posts are sub-tenoned (see [Fig. 103]) to elm sills 10 ft. 6 in. long by 8 in. diameter. Tenons are formed on both ends of the posts, and seatings and mortices at 4-ft. centres are made in both the sills (bottom rails) and plates (top rails) to receive them.

Fig. 103.—Fixing Middle Post of Canopy to Sill.
 Fig. 104.—Details of Joints of Rails, Struts, and Posts for Canopy.

Fig. 105.—Securing Cross Rails to Plates and Posts of Canopy.

The short rails are 4 in. in diameter by 3 ft. 6 in. long, and are stub-tenoned and pinned to the posts at a height of 3 ft. 9 in. from the ground line. The struts also are tenoned and pinned to the middle posts and sills, as shown in [Fig. 104], where, it will be noticed, the struts are in one piece and the braces in two, the latter being hollowed to fit in the angles and over the struts.

Fig. 106.

Fig. 107.

Figs. 106 and 107.—Hook and Thimble for Canopy.

When all the members are ready for the final drive home, the tenons of the rails should be just entered to the posts; the struts and braces are next placed in position and driven up, then the sill and plate are entered and driven home, and finally the several joints are secured with oak pins. This operation will be carried out better with the work in a horizontal position. When the two sides are so far completed, they may be erected in position and fixed with temporary battens, at a distance apart of 7 ft. 9 in. centres, while the top cross rails are being fitted.