A mortise is a cavity cut into a timber to receive a tenon.
There are several kinds of mortises.
Open mortise – A mortise that has only three sides. (See bridle joint).
Stub mortise or “suicide” joint – A shallow mortise, depth depends on the size of the timber; also a mortise that does not go through the work-piece (as opposed to a “through mortise”). the back is wider, or taller, than the front, or opening. The space for the wedge initially allows room for the tenon to be inserted, the presence of the wedge, after the tenon has been engaged, prevents its withdrawal. Sometimes called a “suicide” joint – since it is strictly a “one way trip”.
Through wedged half-dovetail – A wedged half-dovetail mortise that passes entirely through the piece.
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 tenons.
Stub tenon – A short tenon; depth 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”).
Tusk tenon – A kind of mortise and tenon joint that uses a wedge-shaped key to hold the joint together.
Through tenon – A tenon that passes entirely through the piece of wood it is inserted into, being clearly visible on the back side.
Teasel 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.
Feather tenon – A round-shouldered machined fillet or feather which is glued into a machine (router) made slot or mortise on each side of the joint.
Generally the size of the mortise and tenon is related to the thickness of the timbers. It is considered good practice to proportion the tenon as 1/3rd the thickness of the rail, or as close to this as is practical. The haunch, the cut away part of a sash corner 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.
Mortise And tenon is an ancient joint and has been found joining the wooden planks of the “Khufu ship”, a 43.6 m long vessel sealed into a pit in the Giza pyramid complex of the Fourth Dynasty around 2,500 BC. It has also been found in archeological sites in the Middle East, Europe and Asia. The 30 sarsen stones of Stonehenge were dressed and fashioned with mortise and tenon joints before they were erected between 2600 and 2400 B.C.
Finger Joint – Box Joint – Comb Joint
The finger joint – (Also known as “box joint” or “comb joint”) is made by cutting a set of complementary rectangular cuts in two pieces of wood, which are then glued. To visualize a finger joint simply interlock the fingers of your hands at a ninety degree angle; hence the name “finger joint.” It is stronger than a butt or lap joint, and often forms part of the overall look of the piece.
The history of the finger joint is believed to have begun with wooden produce boxes or crates in the days before modern, man-made materials. Finger joints were originally cut by hand with saws and sharp chisels. In modern times they are easily and quickly made with a table saw or router and a jig or fixture, which can be shop-made or purchased from a specialty woodworking supply store. A finger joint jig typically consists of a moving fence with an indexing pin that is used to evenly space out the cuts. The fence is moved over a cutting blade making a cut that is then moved over the indexing pin so the next cut can be made.
The strength of a finger joint comes from the long-grain to long-grain contact between the fingers, which provides a solid gluing surface. The number of contact points also allows for more gluing surface as opposed to a butt joint or a rabbet joint.
The Dovetail Joint Pre Dates Written History As Shown On This Romanian Church
A dovetail joint or simply dovetail is a joint technique most commonly used in woodworking joinery. Noted for its resistance to being pulled apart (tensile strength), the dovetail joint is commonly used to join for example the sides of a drawer to the front. A series of pins cut to extend from the end of one board interlock with a series of tails cut into the end of another board. The pins and tails have a trapezoidal shape. Once glued, a wooden dovetail joint requires no mechanical fasteners.
The dovetail joint pre-dates written history. Some of the earliest known examples of the dovetail joint are in furniture entombed with mummies dating from First Dynasty of ancient Egypt, as well the tombs of Chinese emperors. The dovetail design is an important method of distinguishing various periods of furniture.
Dovetails can be cut by hand or by machines, often with an electric router and using one of a range of commercially available jigs or templates. Although it is technically a straight forward process, hand-cutting dovetails requires a high degree of accuracy to ensure a snug fit and so can be difficult to master. The pins and tails must fit together with no gap between them so that the joint interlocks tightly with no movement. Thus the cutting of dovetails by hand is regarded as a mark of skill on the part of the craftsperson.
It Takes A Master Craftsman To Hand Cut Perfect Joints
The angle of slope varies according to the wood used. Typically the slope is 1:6 for softwoods and a shallower 1:8 slope for hardwoods. Often a slope of 1:7 is used as a compromise – perhaps using a dovetail template for marking out.
When being cut by hand, there are two schools of thought as to whether the pins or the tails should be cut first. For pins first, the pins are laid out and cut by the chosen method, then the outline of the pins is transferred to the face of the tail board. For tails first, the tails are laid out and cut and then the outline is transferred to the end grain of the pin board. Each has advantages and it is a personal choice as to which is chosen.
Hand cut dovetails can often be distinguished from machine-cut dovetails by the width of the pins. It is possible to have pins that are almost triangular when cut by hand that are not possible when cut with a router, owing to the thickness of the router bit’s shank. These narrow pins are known as London Pins.
A through dovetail joint (also known as plain dovetail) joint, where the end grain of both boards is visible when the joint is assembled. Through dovetails are common in carcass and box construction. Traditionally, the dovetails would have often be covered by a veneer. However, dovetails have become a signature of craftsmanship and are generally considered a feature, so they are rarely concealed in contemporary work.
A half-blind dovetail is used when the craftsman does not wish end grain to be visible from the front of the item. The tails are housed in sockets in the ends of the board that is to be the front of the item so that their ends cannot be seen. Half-blind dovetails are commonly used to fasten drawer fronts to drawer sides. This is an alternative to the practice of attaching false fronts to drawers constructed using through dovetails.
The sliding dovetail is a method of joining two boards at right angles, where the intersection occurs within the field of one of the boards, that is not at the end. This joint provides the interlocking strength of a dovetail. Sliding dovetails are assembled by sliding the tail into the socket. It is common to slightly taper the socket, making it slightly tighter towards the rear of the joint, so that the two components can be slid together easily but the joint becomes tighter as the finished position is reached.
The full-blind dovetail obscures the mechanics of the joint altogether. This variant is used in fine work when the craftsperson requires the strength of a dovetail but without the visual intrusion of the interlocking pins and tails. Two versions of this joint are the secret double-lapped dovetail and the full-blind mitered dovetail. The former presents a very thin section of end grain on one edge of the joint, whilst the latter does not. When used in drawer construction, a “full-blind dovetail” is known as a “French dovetail.”
Some of these ancient joints and has been found joining the wooden planks of the “Khufu ship”, a 43.6 m long vessel sealed into a pit in the Giza pyramid complex of the Fourth Dynasty around 2,500 BC. It has also been found in archeological sites in the Middle East, Europe and Asia. 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 show that by the end of the Neolithic, mortise and tenon joinery was employed in Chinese construction. The 30 sarsen stones of Stonehenge were dressed and fashioned with mortise and tenon joints before they were erected between 2600 and 2400 B.C.
A butt joint is a joinery technique in which two members are joined by simply butting them together. The butt joint is the simplest joint to make since it merely involves cutting the members to the appropriate length and butting them together. It is also the weakest because unless some form of reinforcement is used (see below) it relies upon glue alone to hold it together. Because the orientation of the members usually present only end grain to long grain gluing surface, the resulting joint is inherently weak.
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 full width of the tenon member.
The corner bridle joint (also known as a slot mortise and tenon) joins two members at their respective ends, forming a corner. This form of the joint is commonly used to house a rail in uprights, such as legs. It provides good strength in compression and is fairly resistant to racking, although a mechanical fastener or pin is often required. The bridle joint is very popular in workbench construction.
A Butterfly joint is a type of joint used either to hold two or more wooden boards together or to keep two halves of a board that have already started to split from splitting further. They may also be used to stabilize the core of a knothole, preventing it from dropping out over time. A butterfly joint resembles two dovetails connected at the narrow part. A negative of the hole is cut out of the board the butterfly will be placed in and the butterfly is then fitted, keeping the joint together. The wood used for the butterfly is usually a contrasting wood, often walnut.
Coping or scribing is the woodworking technique of shaping the end of a moulding or frame component to fit the contours of an abutting member. Most English speaking countries outside the US use the terms scribe and scribing. Coping is commonly used in the fitting of skirting and other moldings in a room. It allows for clean joints between intersecting members when walls are not square to each other. The other method of fitting these moldings that is commonly used is the mitre joint but this technique relies upon the walls being at 90Â° to each other for neat results.
Coping is only ever used for internal corners. External corners are always mitered. The main reason that scribed joints are used is that timber shrinks in width far more than it does in length. By using a scribed joint rather than an internal mitre joint the effect of shrinkage is minimized. Also it is possible to arrange the scribed joints pointing away from the most common viewpoint (usually the doorway of a room) and so present the best appearance.
A scribed joint (right end of sketch) is derived from an internal mitre cut (left end) by cutting along the inside face of the mitre cut at a right angle to the board, typically with a coping saw.
Coping is also commonly used in cabinet making for moldings and frame components. The rails in frame and panel construction are commonly cope cut to fit the profile of the stiles. The technique is also common in the construction of doors and windows.
Frame and panel construction (also called “rail and stile”) is a woodworking technique often used in the making of doors, wainscoting, and other decorative features for cabinets, furniture, and homes. The basic idea is to capture a ‘floating’ panel within a sturdy frame, as opposed to techniques like slab drawer fronts which are simply single pieces of material with exposed end-grains. Usually, the panel is not glued to the frame – it is left to ‘float’ within it so that seasonal movement of the wood comprising the panel does not distort the frame.
Frame and panel construction at its most basic consists of five members: The panel and the four members which make up the frame. The vertical members of the frame are called stiles while the horizontal members are known as rails. A basic frame and panel item consists of a top rail, a bottom rail, two stiles, and a panel. This is a common method of constructing cabinet doors and these are often referred to as a five piece door.
In larger panels it is common to divide the panel into one or more sections. To house the extra panels, dividing pieces known as mid rails and mid stiles or muntins are added to the frame.
Pocket-Hole Joinery, Pocket-Screw Joinery, or Kreg Joinery involves drilling a hole at an angle into one work-piece, and then joining it to a second work-piece with a self-tapping screw. The technique, in addition to doweling, has its roots in ancient Egypt. Egyptians clamped two work-pieces together and bored a hole at an angle from the outside work-piece into the second work-piece. They then inserted a dowel with glue, and cut it off flush with the outermost surface.
A rabbet (also known as rebate) is a recess or groove cut into the edge of a piece of machinable material, usually wood. When viewed in cross-section, a rabbet is two-sided and open to the edge or end of the surface into which it is cut. The spelling rabbet is probably a derivation of rebate, the latter being more common outside of North America. An example of the use of a rabbet is in a glazing bar where it makes provision for the insertion of the pane of glass and putty. It may also accommodate the edge of the back panel of a cabinet. It is also used in door and casement window jambs.
Tongue and groove joint A strong joint, the tongue and groove joint is widely used for re-entrant angles. The effect of wood shrinkage is concealed when the joint is beaded or otherwise moulded. In expensive cabinet work, glued dovetail and multiple tongue and groove are used. Tongue and groove or T&G is a method of fitting similar objects together, edge to edge, used mainly with wood: flooring, parquetry, panelling, and similar constructions. Tongue and groove joints allow two flat pieces to be joined strongly together to make a single flat surface. Before plywood became common, tongue and groove boards were also used for sheathing buildings and to construct concrete formwork.
Solid parquet boards with tongues on the right sides of the boards and grooves on the left sides. Grooves are also visible on the near ends; the far ends are tongued.
Each piece has a slot (the groove) cut all along one edge, and a thin, deep ridge (the tongue) on the opposite edge. The tongue projects a little less than the groove is deep. Two or more pieces thus fit together closely. The joint is not normally glued, as shrinkage would then pull the tongue off. For many uses, tongue and groove boards have been rendered obsolete by the introduction of plywood and later composite wood boards, but the method is still used in good-quality flooring. Plywood may also be tongued all round to fit it flush into a framed structure, and plywood for sub-floors used in platform framing is often supplied with tongue and groove edges.When joining thicker materials, several tongue and groove joints may be used one above the other.
A dado (US and Canada), housing (UK) or trench (Europe) is a slot or trench cut into the surface of a piece of machinable material, usually wood. When viewed in cross-section, a dado has three sides. A dado is cut across, or perpendicular to, the grain and is thus differentiated from a groove which is cut with, or parallel to, the grain. A dado may be through, meaning that it passes all the way through the surface and its ends are open, or stopped, meaning that one or both of the ends finish before the dado meets the edge of the surface.
Dougong Chinese: 斗拱; pinyin: dǒugǒng
Dougong (simplified Chinese: 斗拱; traditional Chinese: 斗拱; pinyin: dǒugǒng) is a unique structural element of interlocking wooden brackets, one of the most important elements in traditional Chinese, Japanese, Korean, Malaysian and Singaporian architecture. The use of dougong first appeared in buildings of the late centuries BC and evolved into a structural network that joined pillars and columns to the frame of the roof.
Diagram of bracket and cantilever arms from the building manual Yingzao Fashi (published in 1103) of the Song Dynasty.
Dougong was widely used in the ancient Chinese during the Spring and Autumn Period (770 to 476 BC) and developed into a complex set of interlocking parts by its peak in the Tang and Song periods. The pieces are fit together by joinery alone without glue or fasteners, due to the precision and quality of the carpentry. After the Song Dynasty, brackets and bracket sets became more ornamental than structural when used in palatial structures and important religious buildings, no longer the traditional dougong.
Dougong inside the East Hall timber hall of Foguang Temple, built in 857 during the Tang Dynasty
Lost Art ? – We Can Provide The Replacement Parts Made In The Same Hand
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 show that by the end of the Neolithic, mortise and tenon joinery was employed in Chinese construction. This was when Chinese construction was done with pride.
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