Solid hardwoods are cut and shaped into pieces that provide the structural integrity of the furniture. These pieces include the legs, frame and posts that support the weight of the table, chair, or cabinet. Frame pieces are joined in various ways and given additional strength with bonding glues to check if a piece of furniture is joined properly, lift it by one corner. The entire piece should remain rigid and retain its shape with little or no wracking or twisting.
The common mortise and tenon joint is normally used in the construction of tables and chairs. The joint is reliable is a suitable glue such as PVA or cascamite is used. The problem associated with the basic mortice and tenon is that over time the joint can come apart especially if it is expected to hold the weight of a person - such as the joints of a chair.
To strengthen the joint we utilize dowell rod, this helps keep the joint together even when it is under great pressure. This is used as a joint on chairs and other pieces of furniture so that the joints do not break apart when extra weight is applied.
The dovetail joint is very strong because of the way the ‘tails' and ‘pins' are shaped. This makes it difficult to pull the joint apart and virtually impossible when glue is added. There are different types of dovetail joint and when cut accurately they are very impressive and attractive.
This type of dovetail joint is often used for draws where the joint can only be seen from one side. The joint is very strong as are all dovetail joints. This type of joint is sometimes used as the joint for book cases and cabinets.
The Frame and Panel
The tongue and groove system secures the panel within the frame without glue or nails and permits the panel to float within the frame to accommodate its slight expansion and contraction due to changes in humidity.
Additionally, transverse braces-whose number depends on the length of the panel-slide into shallow dovetail housings cut into the bottom of the panel, both supporting the thin panel and preventing its warping.