CONSTRUCTION.

Cutting the Rafters.—­If floor space is available, chalk out accurately the external outline of a pair of rafters (80 inches long each before shaping) and a line joining their lower ends.  Then draw a line bisecting the ridge angle.  With this template as guide the rafters can be quickly cut to shape.  Another method is to cut one rafter out very carefully, making a notch for half the width of the ridge, and to use it as a pattern for the rest.  In any case the chalked lines will prove useful in the next operation of pairing the rafters and uniting them by a tie just under the ridge notch.  Cut a 4 by 1 inch notch at the bottom of each rafter, on the outside, for the base piece.  The two end pairs have the B pieces (Fig. 14) nailed on to them, and r3 the tie t, which should be in line with the rafters.  The other three pairs require temporary ties halfway up to prevent straddling during erection.

Door Frames and Doors.—­The method of fixing the frame of the door at the run end is shown in Fig. 14.  The material for the frame being 1/2 inch thicker than that of the rafters, there is room for shoulders at the top angles, as indicated by dotted lines.  The door frame at the house end is of the same thickness as r1 so that no overlapping is possible.  This being the case, screws should be used in preference to nails, which are liable to draw a sloping face out of position as they get home.

[Illustration:  Fig. 14.—­On left, elevation of end of run; on right, door for run.]

The doors are made of 2 by 2 inch stuff, halved at the corners.  Cut out the top and bottom of the two sides; lay them on the floor so as to form a perfect rectangle, and nail them together.  The strut is then prepared, care being taken to get a good fit, as any shortness of strut will sooner or later mean sagging of the door.  Cut the angles as squarely as possible, to ensure the strut being of the same length both inside and out.

Note.—­As the door is rectangular, it does not matter which corners are occupied by the ends of the strut; but when the door is hung, the strut must run relatively to the side on which the hinges are, as shown in Fig. 14.  Amateurs—­even some professionals—­have been known to get the strut the wrong way up, and so render it practically useless.

Covering the Ends of the House.—­The ends of the house should be covered before erection, while it is still possible to do the nailing on the flat.  The run end is boarded right over, beginning at the bottom, and allowing each board to overlap that below it by 1 inch.  The board ends are flush with the outer sides of the rafters.  When boarding is finished, cut (with a pad saw) a semicircular-topped run hole, 14 inches high and 8 inches wide, in the middle of the bottom.  Any structural weakness caused by severing the two lowest boards is counteracted by the two grooved pieces in which the drop-door moves.