Removing Haunching.—After removing the mortise hole, the small portion which is called the haunching will require to be removed with a chisel. This calls for no special remark, as it is clearly shown in [Figs. 187 and 188]. [Fig. 186] shows an everyday type of mortise and tenon joint separated; it is used in cases where a straight joint is required on the upper or lower edge of the work, whereas the upper rail of [Fig. 176] shows the full haunch on the top edge. In cases such as [Figs 187 and 188], where the edges of the frames are grooved to receive panels, etc., the width of the tenon is reduced by the width of the groove.
| Fig. 185.—Mortise with Side Removed. | Fig. 186.—The Joint Separated. |
| Fig. 187.—Removal of Haunching. | Fig. 188.—Haunching with Groove above. |
This must be remembered by the worker when marking out his stiles with the marking knife. [Fig. 187] (right-hand sketch) shows the haunch, tenon, and groove G at the bottom. [Fig. 188] (left-hand illustration) shows G (groove) at top, and HH (the haunch) at the bottom. Tenons may be glued together and wedged as shown at [Fig. 176] if for inside work; but if for outside work they are generally smeared with thick paint and wedged up. For light-class cabinet work it is usual to cut the mortise about seven-eighths of the distance through the stile and make the tenon to match it; the edge of the finished work does not then show any indication of the joint, and it leaves a nice clean surface at the edge of the work for polishing or varnishing.
Fig. 189.—Interlocking Joint for Seat Rails of Chair to Leg.
Interlocking Chair Joint.—A joint designed with a view to strengthening the construction of chairs at the point where they are weakest is shown in [Fig. 189]. The joint is an interlocking one so arranged that, once the chair is glued up, no motion of the side rail can be possible. The groove in the side rail tenon is cut in such a manner that, on the insertion of the back rail tenon, the joint actually draws up and, having done so, is locked in position. The exact location of this groove is obtained in a similar manner to that used in marking out tenons for drawbore pinning, i.e., the tenon is inserted in its mortise and the position of the back rail mortise transferred to it, after which the lines are set back by 1⁄64 in. (approximately) to cause the joint to draw.
From the illustration the construction of the joint should be clear. The method is particularly adapted to a section of rectangular form where one side is longer than the other, such as the back leg of a chair, as this shape allows for the accommodation of the extra length of tenon required.