Fig. 160.
90. Directions for Mortise.
—(1) From one end of the piece measure and mark with the knife point the respective distances to the two edges of the mortise. (2) Square lines across the face edge and the two broad surfaces at these points. (3) Set the gage equal to the required distance from the face edge to the nearer edge of the mortise and mark between the lines. (4) Set the gage equal to the required distance from the face edge to the farther edge of the mortise and mark between the lines. Make both gage lines on face side and side opposite as well. (5) Cut the mortises. First, bore a series of holes thru the mortise, using a bit somewhat smaller than the width of the mortise. Bore these holes so that they connect one with another. (6) Place the piece on a chiseling board and, taking thin cuts about half way thru, work from the middle of the mortise out to within one thirty-second of an inch of the knife and gage lines. (7) Reverse and chisel from the other side, finishing it; then chisel the first side out to the lines. Test the sides of the mortise with a straight edge—the blade of the chisel makes a good one—to see that they are cut straight. [Fig. 161].
Fig. 161.
91. Directions for Mortise in the Tenon.
—(1) Lay out the sides of the mortise for the key before the sides and shoulders of the tenons are cut. From the shoulder line of the tenon, measure toward the end a distance slightly less—about one thirty-second of an inch—than the thickness of the member thru which the tenon is to pass. This is to insure the key’s wedging against the second member. (2) Square this line across the face edge and on to the side opposite the face side. (3) On the top surface measure from the line just squared around the piece a distance equal to the width the key is to have at this point when in place. [Fig. 158], A B. (4) Square a pencil line across the surface at this point. (5) In a similar manner, measure and locate a line on the opposite side, C D, [Fig. 158]. (6) Set the gage and mark the side of the mortise nearer the face edge on face side and side opposite. (7) Reset, and from the face edge gage the farther side of the mortise, marking both sides. (8) This mortise may be bored and chiseled like the one preceding. As one side of the mortise is to be cut sloping, a little more care will be needed.
Fig. 162.