Construction in living room furniture, especially in the arts and crafts lines, is a very important factor. In some of the most desirable chairs the stretchers, seat rails and back slats are mortised, tenoned and pinned. After this is done all of the parts of the chairs are clamped together under a high pressure which insures tight joints and adds necessary strength. Seating pieces have nicely fitted corner blocks which are glued and screwed, thus adding to their strength. These can be seen by upturning a chair or rocker. The arms of chairs are usually subjected to severe tests and if the back slats are set in and pinned with wooden pins to the back post, a rigid setting is insured.

Front chair posts with a tenon cut on them and mortised through the arms and securely fastened with a wooden pin driven through the arm .and in the post, make a firm construction.

There are other structural devices which are ornamental as well as strong; for example, when the stretcher of the table is mortised through the leg and left projecting on the opposite side, held in place by a wooden pin driven through both leg and stretcher, or when a table stretcher is mortised through the leg and a wooden key is driven through the outside end. In some of the cheaper furniture the appearance may he the same, hut close scrutiny will reveal the fact that the projection does not go through the table leg, but is a piece of wood bradded on. This is sometimes done on the arms of chairs to give the impression that the post goes through the arm.

Wherever surfaces are exposed, it is important to have as perfect glue joints as possible. The tongue and groove joints indicate a groove as cut into each piece and a strip of wood called a tongue is so placed that it enters both grooves when the pieces are joined and glued. The "V" joint is a groove cut into one piece and a ridge that fits the groove left on the other piece. They are clamped together in large glue presses.