Joinery is a part of
woodworking
Woodworking is the skill of making items from wood, and includes cabinet making (cabinetry and furniture), wood carving, joinery, carpentry, and woodturning.
History
Along with stone, clay and animal parts, wood was one of the first mate ...
that involves joining pieces of
wood
Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin ...
,
engineered lumber
Engineered wood, also called mass timber, composite wood, man-made wood, or manufactured board, includes a range of derivative wood products which are manufactured by binding or fixing the strands, particles, fibres, or veneers or boards of woo ...
, or synthetic substitutes (such as
laminate), to produce more complex items. Some woodworking joints employ mechanical fasteners, bindings, or adhesives, while others use only wood elements (such as dowels or plain mortise and tenon fittings).
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
cabinetry
A cabinet is a case or cupboard with shelves and/or drawers for storing or displaying items. Some cabinets are stand alone while others are built in to a wall or are attached to it like a medicine cabinet. Cabinets are typically made of wood (s ...
or
furniture, although some concepts overlap. While a form of
carpentry elsewhere, in British English usage it is distinguished from it, which is considered to be a form of structural
timber
Lumber is wood that has been processed into dimensional lumber, including beams and planks or boards, a stage in the process of wood production. Lumber is mainly used for construction framing, as well as finishing (floors, wall panels, w ...
work.
History
Many traditional wood joinery techniques use the distinctive material properties of
wood
Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin ...
, often without resorting to mechanical fasteners or adhesives. While every culture in which pieces of wood are joined to make furniture or structures has a joinery tradition, wood joinery techniques have been especially well-documented, and are celebrated, in the Indian,
Chinese
Chinese can refer to:
* Something related to China
* Chinese people, people of Chinese nationality, citizenship, and/or ethnicity
**''Zhonghua minzu'', the supra-ethnic concept of the Chinese nation
** List of ethnic groups in China, people of ...
, European, and Japanese traditions. Because of the physical existence of Indian and Egyptian examples, we know that furniture from the first several dynasties show the use of complex joints, like the Dovetail, over 5,000 years ago. This tradition continued to other later Western styles. The 18th-century writer
Diderot included over 90 detailed illustrations of wood joints in his comprehensive encyclopedia. While Western techniques focused on concealment of joinery, the Eastern societies, though later, did not attempt to "hide" their joints. The Japanese and Chinese traditions in particular required the use of hundreds of types of joints. The reason was that nails and glues used did not stand up well to the vastly fluctuating temperatures and humid weather conditions in most of Central and South-East Asia. As well, the highly resinous woods used in traditional
Chinese furniture
The forms of Chinese furniture evolved along three distinct lineages which dates back to 1000 BC, based on ''frame and panel'', ''yoke and rack'' (based on post and rail seen in architecture) and ''bamboo'' construction techniques. Chinese ...
do not glue well, even if they are cleaned with solvents and attached using modern glues.
As with all trades new developments have evolved to help speed, simplify, or improve joinery. These include
"biscuit" and
"domino" joints, and
pocket screw joinery.
Properties of wood
Many wood joinery techniques either depend upon or compensate for the fact that wood is
anisotropic: its material properties are different along different dimensions.
This must be taken into account when joining wood parts together, otherwise the joint is destined to fail. Gluing boards with the grain running perpendicular to each other is often the reason for split boards, or broken joints. Furniture from the 18th century, while made by master craftsmen, did not take this into account. The result is this masterful work suffers from broken bracket feet, which was often attached with a glue block which ran perpendicular to the base pieces. The glue blocks were fastened with both glue and nails, resulting in unequal expansion and contraction between the pieces. This was also the cause of splitting of wide boards, which were commonly used during that period.
In modern woodworking it is even more critical, as heating and air conditioning cause major changes in the moisture content of the wood. All woodworking joints must take these changes into account, and allow for the resulting movement.
Strength
Wood is stronger when stressed along the
grain (longitudinally) than it is when stressed across the grain (radially and tangentially). Wood is a natural composite material; parallel strands of
cellulose
Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. Cellulose is an important structural component of the primary cell w ...
fibers are held together by a
lignin binder. These long chains of fibers make the wood exceptionally strong by resisting stress and spreading the load over the length of the board. Furthermore, cellulose is tougher than lignin, a fact demonstrated by the relative ease with which wood can be split along the grain compared to across it.
Different species of wood have different strength levels, and the exact strength may vary from sample to sample.
Dimensional stability
Timber expands and contracts in response to
humidity
Humidity is the concentration of water vapor present in the air. Water vapor, the gaseous state of water, is generally invisible to the human eye. Humidity indicates the likelihood for precipitation, dew, or fog to be present.
Humidity dep ...
, usually much less so longitudinally than in the radial and tangential directions. As
tracheophytes
Vascular plants (), also called tracheophytes () or collectively Tracheophyta (), form a large group of land plants ( accepted known species) that have lignified tissues (the xylem) for conducting water and minerals throughout the plant. They ...
, trees have
lignified tissues which transport resources such as water, minerals and photosynthetic products up and down the plant. While lumber from a harvested tree is no longer alive, these tissues still absorb and expel water causing swelling and shrinkage of the wood in kind with change in humidity. When the dimensional stability of the wood is paramount,
quarter-sawn
Quarter sawing or quartersawing is a woodworking process that produces quarter-sawn or quarter-cut boards in the rip cutting of logs into lumber. The resulting lumber can also be called ''radially-sawn'' or simply ''quartered''. There is wides ...
or
rift-sawn lumber is preferred because its grain pattern is consistent and thus reacts less to humidity.
Materials used for joining
*
Dowels can secure wood joints hold without the use of glue or mechanical fasteners, as in a pinned
mortise and tenon.
*
Glue is highly effective for joining timber when both surfaces of the joint are edge grain. A properly glued joint may be as strong or stronger than a single piece of wood. However, glue is notably less effective on
end-grain surfaces.
Animal glue
Animal glue is an adhesive that is created by prolonged boiling of animal connective tissue in a process called rendering. In addition to being used as an adhesive it is used for coating and sizing, in decorative composition ornaments, and as a ...
is soluble in water, producing joints that can be disassembled using
steam to soften the bond.
* Various mechanical
fastener
A fastener (US English) or fastening (UK English) is a hardware device that mechanically joins or affixes two or more objects together. In general, fasteners are used to create non-permanent joints; that is, joints that can be removed or disman ...
s may be used, the simplest being
nail
Nail or Nails may refer to:
In biology
* Nail (anatomy), toughened protective protein-keratin (known as alpha-keratin, also found in hair) at the end of an animal digit, such as fingernail
* Nail (beak), a plate of hard horny tissue at the tip ...
s and
screw
A screw and a bolt (see '' Differentiation between bolt and screw'' below) are similar types of fastener typically made of metal and characterized by a helical ridge, called a ''male thread'' (external thread). Screws and bolts are used to f ...
s. Glue and fasteners can be used together.
Reinforcing joints
*
Dowel: A small rod is used internal to a joint both to help align and to strengthen the joint. Traditional joints are used with natural timbers as they do not need materials other than the timber itself. for example: Butt joints. Dowel joints are also useful for pegging together weaker, cheaper composite materials such as laminate-faced chipboard, and where limited woodworking tools are available (since only simple drilled holes are needed to take the dowels).
*
Biscuit joints: A small preformed wooden 'biscuit' is inserted in a pre-cut slot to help align an edge or butt joint when gluing.
*
Domino joiner: A trademarked form of biscuit joiner, where a larger piece of preformed wood than a traditional biscuit - referred to as a "domino" - has some of the advantages of dowels and some of biscuits.
[ Monday, June 22, 2020]
Types of wood joints
Traditional
Modern
See also
Footnotes
References
* Lee A. Jesberger (2007). ''Woodworking Terms and Joints''. Pro Woodworking Tips.com
* Bernard Jones (Ed.) (1980). ''The Complete Woodworker''.
* Peter Korn (1993). ''Working with Wood''.
* Sam Allen (1990). ''Wood Joiner's Handbook''. Sterling Publishing.
* Wolfram Graubner (1992). ''Encyclopedia of Wood Joints''. Taunton Press.
* US Forestry Service (1985) ''Water Repellency and Dimensional Stability of Wood'' http://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr50.pdf
External links
Pro Woodworking Tips - WoodworkingBritish Woodworking Federation- not for profit woodworking body advice on joinery in the UK
;Terms and Joints
Craftsmanspace
*
List of French timber framing joints, in French language
custom furniture dubai
{{DEFAULTSORT:Woodworking Joints
Joints
A joint or articulation (or articular surface) is the connection made between bones, ossicles, or other hard structures in the body which link an animal's skeletal system into a functional whole.Saladin, Ken. Anatomy & Physiology. 7th ed. McGraw- ...
Joints
A joint or articulation (or articular surface) is the connection made between bones, ossicles, or other hard structures in the body which link an animal's skeletal system into a functional whole.Saladin, Ken. Anatomy & Physiology. 7th ed. McGraw- ...