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A mortise and tenon (occasionally mortice and tenon)
joint 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- ...
connects two 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 ...
or other material.
Woodworkers 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 materials ...
around the world have used it for thousands of years to join pieces of wood, mainly when the adjoining pieces connect at right angles. Mortise and tenon joints are strong and stable joints that can be used in many projects. They furnish a strong outcome and connect by either gluing or locking into place. The mortise and tenon joint also gives an attractive look. One drawback to this joint is the difficulty in making it because of the precise measuring and tight cutting required. In its most basic form, a mortise and tenon joint is both simple and strong. There are many variations of this type of joint, and the basic mortise and tenon has two components: #the mortise hole, and #the tenon tongue. The tenon, formed on the end of a member generally referred to as a rail, fits into a square or rectangular hole cut into the other, corresponding member. The tenon is cut to fit the mortise hole exactly. It usually has shoulders that seat when the joint fully enters the mortise hole. The joint may be glued, pinned, or wedged to lock it in place. This joint is also used with other materials. For example, it is traditionally used by both stonemasons and
blacksmith A blacksmith is a metalsmith who creates objects primarily from wrought iron or steel, but sometimes from other metals, by forging the metal, using tools to hammer, bend, and cut (cf. tinsmith). Blacksmiths produce objects such as gates, gr ...
s.


Etymology

The noun ''mortise'', "a hole or groove in which something is fitted to form a joint", comes from 1400 from
Old French Old French (, , ; Modern French: ) was the language spoken in most of the northern half of France from approximately the 8th to the 14th centuries. Rather than a unified language, Old French was a linkage of Romance dialects, mutually intelligib ...
(13th century), possibly from
Arabic Arabic (, ' ; , ' or ) is a Semitic languages, Semitic language spoken primarily across the Arab world.Semitic languages: an international handbook / edited by Stefan Weninger; in collaboration with Geoffrey Khan, Michael P. Streck, Janet C ...
, "fastened", past participle of , "cut a mortise in". The word ''tenon'', a noun in English since the late 14th century, developed its sense of "a projection inserted to make a joint" from the Old French "to hold".


History and ancient examples

The mortise and tenon joint is an ancient joint dating back 7,000 years. The first examples, tusked joints, were found in a well near
Leipzig Leipzig ( , ; Upper Saxon: ) is the most populous city in the German state of Saxony. Leipzig's population of 605,407 inhabitants (1.1 million in the larger urban zone) as of 2021 places the city as Germany's eighth most populous, as wel ...
– the world's oldest intact wooden architecture. These were created by early
Neolithic The Neolithic period, or New Stone Age, is an Old World archaeological period and the final division of the Stone Age. It saw the Neolithic Revolution, a wide-ranging set of developments that appear to have arisen independently in several parts ...
Linear Pottery culture The Linear Pottery culture (LBK) is a major archaeological horizon of the European Neolithic period, flourishing . Derived from the German ''Linearbandkeramik'', it is also known as the Linear Band Ware, Linear Ware, Linear Ceramics or Inci ...
, where it was used in the construction of the wooden lining of the wells. Mortise and tenon joints have also been found joining the wooden planks of the "
Khufu ship The Khufu ship is an intact full-size solar barque from ancient Egypt. It was sealed into a pit at the foot of the Great Pyramid of pharaoh Khufu around 2500 BC, during the Fourth Dynasty of the ancient Egyptian Old Kingdom. Like other buried ...
",Ward, Cheryl.
World's Oldest Planked Boats
" in ''Archaeology'' (Volume 54, Number 3, May/June 2001). Archaeological Institute of America.
a long vessel sealed into a pit in the Giza pyramid complex of the
Fourth Dynasty The Fourth Dynasty of ancient Egypt (notated Dynasty IV) is characterized as a "golden age" of the Old Kingdom of Egypt. Dynasty IV lasted from to 2494 BC. It was a time of peace and prosperity as well as one during which trade with other ...
around 2500 BC. Mortise and tenon joints have also been found in ancient furniture from archaeological sites in the Middle East, Europe and Asia. Many instances are found, for example, in ruins of houses in the Silk Road kingdom of Cadota, dating from the first to the 4th century BC. In traditional
Chinese architecture Chinese architecture ( Chinese:中國建築) is the embodiment of an architectural style that has developed over millennia in China and it has influenced architecture throughout Eastern Asia. Since its emergence during the early ancient era, ...
, wood components such as beams, brackets, roof frames, and struts were made to interlock with perfect fit, without using fasteners or glues, enabling the wood to expand and contract according to humidity. Archaeological evidence from Chinese sites shows that, by the end of the Neolithic, mortise and tenon joinery was employed in Chinese construction. The thirty sarsen stones of Stonehenge were dressed and fashioned with mortise and tenon joints before they were erected between 2600 and 2400 BC. A variation of the mortise and tenon technique, called
Phoenician joints Phoenician joints () is a locked mortise and tenon wood joinery technique used in shipbuilding to fasten watercraft hulls. The locked (or pegged) mortise and tenon technique consists of cutting a mortise, or socket, into the edges of two plank ...
(from the Latin ) was extensively used in ancient
shipbuilding Shipbuilding is the construction of ships and other floating vessels. It normally takes place in a specialized facility known as a shipyard. Shipbuilders, also called shipwrights, follow a specialized occupation that traces its roots to befo ...
to assemble hull planks and other watercraft components together. It is a locked (pegged) mortise and tenon technique that consists of cutting two mortises into the edges of two planks; a separate rectangular tenon is then inserted in the two mortises. The assembly is then locked in place by driving a dowel through one or more holes drilled through mortise side wall and tenon.


Description

Generally, the size of the mortise and tenon is related to the thickness of the timbers. It is good practice to proportion the tenon as one third the thickness of the rail, or as close to this as is practical. The haunch, the cut-away part of a
sash corner A sash is a large and usually colorful ribbon or band of material worn around the body, either draping from one shoulder to the opposing hip and back up, or else running around the waist. The sash around the waist may be worn in daily attire, bu ...
joint that prevents the tenon coming loose, is one third the length of the tenon and one-sixth of the width of the tenon in its depth. The remaining two-thirds of the rail, the tenon shoulders, help to counteract lateral forces that might tweak the tenon from the mortise, contributing to its strength. These also serve to hide imperfections in the opening of the mortise.


Types


Mortises

A mortise is a hole cut into a timber to receive a tenon. There are several kinds of mortise: * Open mortise: a mortise that has only three sides. (See
bridle joint A bridle joint is a woodworking joint, similar to a mortise and tenon, in that a tenon is cut on the end of one member and a mortise is cut into the other to accept it. The distinguishing feature is that the tenon and the mortise are cut to the ...
). * Stub mortise: a shallow mortise, the depth of which depends on the size of the timber; also a mortise that does not go through the workpiece (as opposed to a "through mortise"). * Through mortise: a mortise that passes entirely through a piece. * Wedged half- dovetail: a mortise in which the back is wider, or taller, than the front, or opening. The space for the wedge initially leaves room to insert the tenon. The wedge, after the tenon is engaged, prevents its withdrawal. * Through-wedged half-dovetail: a wedged half-dovetail mortise that passes entirely through the piece.


Tenons

A tenon is a projection on the end of a timber for insertion into a mortise. Usually, the tenon is taller than it is wide. There are several kinds of tenon: * Stub tenon: a short tenon, the depth of which depends on the size of the timber; also a tenon that is shorter than the width of the mortised piece so the tenon does not show (as opposed to a "through tenon"). * Through tenon: a tenon that passes entirely through the piece of wood it is inserted into, being clearly visible on the rear side. * Loose tenon: a tenon that is a separate part of the joint, as opposed to a fixed tenon that is an integral part of one of the pieces to be joined. * Biscuit tenon: a thin oval piece of wood, shaped like a biscuit * Pegged (or pinned) tenon: the joint is strengthened by driving a peg or dowel pin (
treenail A treenail, also trenail, trennel, or trunnel, is a wooden peg, pin, or dowel used to fasten pieces of wood together, especially in timber frames, covered bridges, wooden shipbuilding and boat building. It is driven into a hole bored through two ...
) through one or more holes drilled through mortise side wall and tenon; this is common in
timber framing Timber framing (german: Holzfachwerk) and "post-and-beam" construction are traditional methods of building with heavy timbers, creating structures using squared-off and carefully fitted and joined timbers with joints secured by large wooden ...
joints. * Tusk tenon: a kind of mortise and tenon joint that uses a wedge-shaped key to hold the joint together. * Teasel (or teazle) tenon: a term used for the tenon on top of a jowled or gunstock post, which is typically received by the mortise in the underside of a
tie beam A tie, strap, tie rod, eyebar, guy-wire, suspension cables, or wire ropes, are examples of linear structural components designed to resist tension. It is the opposite of a strut or column, which is designed to resist compression. Ties may be ...
. A common element of the English tying joint. * Top tenon: the tenon that occurs on top of a post. * Hammer-headed tenon: a method of forming a tenon joint when the shoulders cannot be tightened with a clamp. * Half shoulder tenon: an asymmetric tenon with a shoulder on one side only. A common use is in framed, ledged, and braced doors.


Gallery

Image:Mortise.svg, A traditional through, wedged, mortise and tenon joint Image:MortiseCornerStub.svg, A stub tenon corner joint Image:MortiseHaunch.svg, A haunched stub tenon corner joint Image:MortiseFoxTail.svg, A foxtail wedged tenon joint Image:PinnedTenon.svg, A pinned corner tenon joint Image:FeatherTenon.svg, A modern feather tenon joint (primarily called a loose tenon)


See also

*
Box joint A box joint is a woodworking joint made by cutting a set of complementary, interlocking profiles in two pieces of wood, which are then joined (usually) at right angles, usually glued. The glued box joint has a high glued surface area resulting i ...
* Dado * Dovetail joint


References

* This article is partly based on a
Quicksilver wiki Neal Town Stephenson (born October 31, 1959) is an American writer known for his works of speculative fiction. His novels have been categorized as science fiction, historical fiction, cyberpunk, postcyberpunk, and baroque. Stephenson's work ...
article a
A Glossary of Terms For Traditional Timber Framing (Timberbee)
under the terms of the GNU Free Documentation License. {{Woodworking Joinery Timber framing