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Mortise and Tenon

History

This is an ancient joint dating back 7,000 years. The first examples, tusked joints, were found in a well near Leipzig Archaeologists in Germany say they've used tree-ring data to identify four ancient water wells as some of the world's oldest timber constructions.

A research team led by the University of Freiburg said the wells excavated at settlements of the first Central European agricultural civilization in the Greater Leipzig region are the oldest known timber constructions in the world, dating to between 5,600 and 4,900 B.C.
Read more: Oldest Timber Construction Unearthed

- the world's oldest intact wooden architecture. It has also been found joining the wooden planks of the "Khufu ship" The Khufu ship is an intact full-size vessel from Ancient Egypt that was sealed into a pit in the Giza pyramid complex at the foot of the Great Pyramid of Giza around 2500 BC. The ship now is preserved in the Giza Solar boat museum. The ship was almost certainly built for Khufu (King Cheops), the second pharaoh of the Fourth Dynasty of the Old Kingdom of Egypt. Like other buried Ancient Egyptian ships, it was apparently part of the extensive grave goods intended for use in the afterlife, and contained no bodies, unlike northern European ship burials. Read more... Khufu Ship, a 43.6 m long vessel sealed into a pit in the Giza pyramid complex of the Fourth Dynasty around 2500 BC. The oldest known use dates from the Early Neolithic Linear Pottery culture, where it was used in the constructing of the wooden lining of water wells.1


It has 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 fourth century BC. In traditional Chinese architecture, 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.1

Mortise

The word mortise is derived from the same Latin stem as are the words mortem, mortify, etc., which in turn are suggestive of death. It is supposed that the usual shape of the mortise resembling the shape of the grave gave rise to the origin of the name. Thus the mortise is the hole in one piece of wood into which the tenon fits.

Tenon

The word tenon is derived from the Latin teno, to hold. From the same Latin stem words as tenacity, tentacle, etc., are derived. The tenon is the part of a joint of wood which fits into the mortise.

Types of Mortise and Tenon Joints

Mortise

  • Plain or simple: shoulders on two sides.
  • Blind: shoulders on three or four sides.
  • Through: tenon projects through, sometimes pinned,
  • Keyed: tenon projects through and has wedged shaped key to hold joint tight.
  • Wedged: where tenon has some form of wedge driven to hold.
  • Open mortise: a mortise that has only three sides.
  • 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.

Tenon

  • Stub tenon: short, 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 back 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 through one or more holes drilled through mortise side wall and tenon; this is common in timber framing 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 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.

Examples

A stub tenon corner joint
A stub tenon corner joint
A haunched stub tenon corner joint
A haunched stub tenon corner joint
A foxtail wedged tenon joint
A foxtail wedged tenon joint

A modern feather tenon joint (primarily called a loose tenon)
A modern feather tenon joint (primarily called a feather tenon)
A traditional through, wedged, mortise and tenon joint
A traditional through, wedged, mortise and tenon joint
A pinned corner tenon joint
A pinned corner tenon joint


Eight common mortise and tenon joints, graphics by Shopsmith
Reference: Shopsmith -- Mortising. https://www.shopsmith.com/ownersite/catalog/mortising. Accessed 9 Dec. 2018.

General uses

  1. Connection between legs and rails, such as in a table.
  2. Connection between rails with other rails, as in a door.

Methods of making Mortise and Tenon joint

  1. By hand: Tenons are laid out and sawed. Faces may be chiseled to fit mortise. Rabbeting plane may be used to finish faces of tenons.
  2. By machine: Tenons may be cut with circular saw or tenoner.
  3. Mortises are made by boring out waste and trimming sides with chisel or by cutting with chisel without boring.
  4. Mortises are cut with “stab’’ mortiser, chain mortiser or hollow chisel mortiser.

Images

blind mortise and tenon
Blind: shoulders on three or four sides
wedge tenons for the foundation beam of a home in France
Wedged tenons for the foundation beam of a home in France
mortise and tenon construction for home building
Mortise and Tenon construction for home building

References

1 Wikipedia contributors. "Mortise and tenon." Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 22 Oct. 2018. Web. 7 Dec. 2018.

Bibliography


  • Hunt, De Witt Talmadge (A Manual For Hand Woodworking) 1925 (Harlow Pub Corp.) Oklahoma City 
  • Wikipedia contributors (Mortise and tenon) https://en.wikipedia.org/w/index.php?title=Mortise_and_tenon&oldid=865203229 (Wikipedia, The Free Encyclopedia.) 

Contributors to this page: admin and John Morris .
Page last modified on Sunday December 9, 2018 08:33:00 PST by admin.