Hammer-headed tenon joints are one method that can be used to join curved members of joinery components.
Joinery is a part of woodworking that involves joining together pieces of timber or lumber, to produce more complex items. Some wood joints employ fasteners, bindings, or adhesives, while others use only wood elements. The characteristics of wooden joints - strength, flexibility, toughness, appearance, etc. - derive from the properties of the materials involved and the purpose of the joint. Therefore, different joinery techniques are used to meet differing requirements. For example, the joinery used to construct a house can be different from that used to make puzzle toys, although some concepts overlap.
The hammer-headed tenon is used to join a curved member to a straight member such as a curved head member to a jamb. The tenon is formed on the jamb and the mortise to receive the tenon is formed on the curved member. The mortise is increased in size to receive a pair of folding wedges each side of the tenon.
A mortiseand tenon joint connects two pieces of wood or of other material. Woodworkers around the world have used it for thousands of years to join pieces of wood, mainly when the adjoining pieces connect at right angles.
The hammer-headed key is used where there is no straight member to form the tenon. It is difficult to form a strong tenon on curved cut timber as the short grain there will weaken it, so two mortise sockets are formed one in each piece and a separate tenon piece called a key is formed to fit. As with the hammer-headed tenon the mortise sockets are increased in size to allow for the folding wedges each side of the tenon.
Wood grain is the longitudinal arrangement of wood fibers or the pattern resulting from this.
When the joint is fitted and glued together it is the folding wedges that give the cramping effect that tightens the shoulder of the joint.
A clamp is a fastening device used to hold or secure objects tightly together to prevent movement or separation through the application of inward pressure. In the United Kingdom and Australia, the term cramp is often used instead when the tool is for temporary use for positioning components during construction and woodworking; thus a G cramp or a sash cramp but a wheel clamp or a surgical clamp.
Both these hammer-headed joints need good attention to detail from the joiner as they are difficult to make completely by machine or power tool.
A joiner is an artisan who builds things by joining pieces of wood, particularly lighter and more ornamental work than that done by a carpenter, including furniture and the "fittings" of a house, ship, etc. Joiners may work in a workshop, because the formation of various joints is made easier by the use of non-portable, powered machinery, or on job site. A joiner usually produces items such as interior and exterior doors, windows, stairs, tables, bookshelves, cabinets, furniture, etc. In shipbuilding a marine joiner may work with materials other than wood such as linoleum, fiberglass, hardware, and gaskets.
Other joints that can be used on curved headed frames are:
Draw dowelled bridle or mortise
Handrail bolts and dowels
