From the line which locates the lower edge of the cross-piece (using the square on the face edge) mark the position (on the opposite corner) of the lower line on the outside edge, by the method given in the previous exercise ([see Fig. 66]), and square this line across the outside edge; then measure the width of the tenon, plus the width of the key, and square the line across.
Fig. 75.
Fig. 76.
(Where work is to be finished on the faces, care should be taken not to mark the work with knife lines, but if auxiliary lines must be used, then mark them with a pencil so that they may be cleaned off when the work is being smoothed.)
Having laid out the keyed mortise lay out the brace mortise, the lower end of which is located 3½ inches below the lower edge of the cross piece; the drawing gives all the dimensions for this.
Take the cross-piece and lay out the tenon in the same way that the tenon in Exercise Number 3 is prepared, using the dimensions that are given in the drawing for the work on hand.
After marking the shoulders of the cross-piece lay out the brace mortise, which is 3½ inches from the shoulder to the farthest end, and mark the other lines as called for in the drawing. Use the single gauge as directed in Exercise Number 3 to mark the side lines of the mortise and tenon, and cut the mortise with the mortising chisel, taking care to cut the ends to the proper angle.
Saw the tenon as previously directed, and after the sides have been cut off, mark the splay on the lower side of the tenon and cut it off with a paring chisel.