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. [1] It is driven into a hole bored through two (or more) pieces of structural wood (mortise and tenon).
The use of wood as a tenon can be traced back over 7,000 years, as archaeologist have found traces of wood nails in the excavation of early Germanic sites. [2] Trenails are extremely economical and readily available, making them a common early building material. [3] Black Locust is a favorite wood when making trunnels in shipbuilding in North America [4] [5] and English Oak in Europe [6] [7] due to their strength and rot resistance, while red oak is typical in buildings. Traditionally treenails and pegs were made by splitting bolts of wood with a froe and shaping them with a drawknife on a shaving horse. Treenails are cut from a single piece of wood and perform well because of the natural grain. The grain of the treenail runs perpendicular to the grain of the receiving mortises which adds structural strength. Treenails are typically 1.25–1.5 inches (32–38 mm) in diameter and are hand whittled with rough facets. The mortise is drilled 1⁄16 inch (1.6 mm) smaller than the treenail to create a tight fit and take advantage of friction in the mortise. In cases where the treenail is 24 inches (61 cm) or longer, the treenail should be shaped 1⁄8 inch (3.2 mm) smaller than the other half. In the same case the mortise is drilled in two parts, with a smaller auger for the smaller part of the treenail and a typical auger for the standard part. Other trenails are tapered with the large end being 1⁄8 inch (3.2 mm) longer than the mortise. After treenails are hammered into the mortise, they can be trimmed, split, and wedged with a small piece of oak that increases friction force. [8] As an alternative to the wedge, the treenail can receive a plug or a punch to the center that expands the entire circumference. While this method prevents leaks by reducing gaps, plugs and punches are more likely to fall out in cold temperatures. Ideally, the nose of the treenail is driven 4–5 cm clear of the timber before being trimmed. [9] Unlike metal nails, trenails can not be removed (without great effort) or reused. As the wood shrinks or expand the fibers create a friction that interlocks it into the mortise snugly. If a treenail breaks or fails but the wood it is fastening remains intact the remaining trenail can be cut out and replaced with a larger treenail that fits snugly. In addition, treenails have the ability to move over time and retain structural integrity.
Early mortise and tenon trusses with spans of less than 30 feet (9 m) used treenail fasteners. When used in a truss, the connecting mortises are drilled off center such that when the treenail is inserted it creates a tighter joint. Because of the large number of trenails required in a truss, the treenails can be turned on a lathe with a head and a tapered end, often kept extra-long for the tightest fit. The bottom chord often requires 2–3 pegs and is the weakest part of the truss. Hence the treenail can not prevent failure in spans of over 30 feet (9 m). In cases where significant shrinkage may occur, it may be necessary to use iron U-straps or reinforcements. [10]
Ancient shipbuilding used treenails to bind the boat together. They had the advantage of not giving rise to "nail-sickness", a term for decay accelerated and concentrated around metal fasteners. Increased water content causes wood to expand, so that treenails gripped the planks tighter as they absorbed water. [11] However, when the treenail was a different wood species from the planking, it usually caused rot. Treenails and iron nails were most common until the 1780s when copper nails over copper sheathing became more popular. [3] As late as the 1870s, merchant ships used treenails and iron bolts, while higher quality ships used copper and yellow metal bolts and dumps. In the 1870s, treenails were typically used in a ratio of four treenails to one bolt, although sometimes more bolts were used. In later corvettes, the ratio was changed to two treenails to one bolt. [12]
Similar wooden trenail fastenings were used as alternatives to metal spikes to secure railroad rail-support "chairs" to wooden sleepers (ties) in early Victorian times. Treenails were extensively used constructing railroads in North England. [13]
In woodworking and construction, a nail is a small object made of metal which is used as a fastener, as a peg to hang something, or sometimes as a decoration. Generally, nails have a sharp point on one end and a flattened head on the other, but headless nails are available. Nails are made in a great variety of forms for specialized purposes. The most common is a wire nail. Other types of nails include pins, tacks, brads, spikes, and cleats.
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 before recorded history.
A mortiseand tenon joint connects two pieces of wood or 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.
Carvel built or carvel planking is a method of boat building in which hull planks are laid edge to edge and fastened to a robust frame, thereby forming a smooth surface. Traditionally the planks are neither attached to, nor slotted into, each other, having only a caulking sealant between the planks to keep water out. Modern carvel builders may attach the planks to each other with glues and fixings. It is a "frame first" method of hull construction, where the shape is determined by the framework onto which the planks are fixed. This is in contrast to "plank first" or "shell first" methods, where the outer skin of the hull is made and then reinforced by the insertion of timbers that are fitted to that shape. The most common modern "plank first" method is clinker construction; in the classical period "plank first" involved joining the edges of planks with mortise and tenon joints within the thickness of the timbers, superficially giving the smooth-hull appearance of carvel construction, but achieved by entirely different means.
Boat building is the design and construction of boats and their systems. This includes at a minimum a hull, with propulsion, mechanical, navigation, safety and other systems as a craft requires.
A joist is a horizontal structural member used in framing to span an open space, often between beams that subsequently transfer loads to vertical members. When incorporated into a floor framing system, joists serve to provide stiffness to the subfloor sheathing, allowing it to function as a horizontal diaphragm. Joists are often doubled or tripled, placed side by side, where conditions warrant, such as where wall partitions require support.
A sewn boat is a type of wooden boat which is clinker built with its planks sewn, stitched, tied, or bound together with tendons or flexible wood, such as roots and willow branches. Sewn boat construction techniques were used in many parts of the world prior to the development of metal fasteners, and continued to be used long after that time for small boats to reduce construction costs where metal fasteners were too expensive.
Clinker-built is a method of boat building in which the edges of hull planks overlap each other. Where necessary in larger craft, shorter planks can be joined end to end, creating a longer strake or hull plank.
Framing, in construction, is the fitting together of pieces to give a structure support and shape. Framing materials are usually wood, engineered wood, or structural steel. The alternative to framed construction is generally called mass wall construction, where horizontal layers of stacked materials such as log building, masonry, rammed earth, adobe, etc. are used without framing.
A Howe truss is a truss bridge consisting of chords, verticals, and diagonals whose vertical members are in tension and whose diagonal members are in compression. The Howe truss was invented by William Howe in 1840, and was widely used as a bridge in the mid to late 1800s.
A rail fastening system is a means of fixing rails to railroad ties or sleepers. The terms rail anchors, tie plates, chairs and track fasteners are used to refer to parts or all of a rail fastening system. The components of a rail fastening system may also be known collectively as other track material, or OTM for short. Various types of fastening have been used over the years.
Ancient boat building methods can be categorized as one of hide, log, sewn, lashed-plank, clinker, shell-first, and frame-first. While the frame-first technique dominates the modern ship construction industry, the ancients relied primarily on the other techniques to build their watercraft. In many cases, these techniques were very labor-intensive and/or inefficient in their use of raw materials. Regardless of differences in ship construction techniques, the vessels of the ancient world, particularly those that plied the waters of the Mediterranean Sea and the islands of Southeast Asia were seaworthy craft, capable of allowing people to engage in large-scale maritime trade.
A timber roof truss is a structural framework of timbers designed to bridge the space above a room and to provide support for a roof. Trusses usually occur at regular intervals, linked by longitudinal timbers such as purlins. The space between each truss is known as a bay.
The Ma'agan Michael Ship is a well-preserved 5th-century BCE boat discovered off the coast of Kibbutz Ma'agan Michael, Israel, in 1985. The ship was excavated and its timber immersed in preservation tanks at the University of Haifa, undergoing a seven-year process of impregnation by heated polyethylene glycol (PEG). In March 1999, the boat was reassembled and transferred to a dedicated wing built at the Hecht Museum, on the grounds of the university. The boat has provided researchers with insights into ancient methods of shipbuilding and the evolution of anchors.
The Sparrow-Hawk was a 'small pinnace' similar to the full-rigged pinnace Virginia that sailed for the English Colonies in June 1626. She is the earliest ship to participate in the first decades of English settlement in the New World to have survived to the present day.
Wood splitting is an ancient technique used in carpentry to make lumber for making wooden objects, some basket weaving, and to make firewood. Unlike wood sawing, the wood is split along the grain using tools such as a hammer and wedges, splitting maul, cleaving axe, side knife, or froe.
Discovered by divers from the French Navy Diving School in 1967, the archaeological investigations of the Roman wreck at Madrague de Giens constituted the first large scale, "truly scientific underwater excavation[s] carried out in France". The wreck lies at around 18 to 20 metres depth off the coast of the small fishing port of La Madrague de Giens on the Giens Peninsula, east of Toulon, on the southern Mediterranean coast of France. Sunk around 75–60 BCE, the vessel has been found to be "a large merchantman of considerable tonnage—400 tons deadweight with a displacement of around 550 tons", making it one of the largest Roman wrecks excavated, with only the wreck at Albenga, Italy exceeding it at the time of its discovery. The vessel wrecked at Madrague de Giens measured around 40 metres in length; has a "wine glass" section which would have given better ability to sail to windward; displayed extended raking of the stem and stern; and had two masts. The hull was characterised by a reverse stempost in the shape of a ram with a big cutwater which "must have given... [the] craft high-performance sailing qualities". The ship sank while transporting a large cargo of wine and black glazed pottery from Italy. It is not known why it sank.
Lashed-lug boats are ancient boat-building techniques of the Austronesian peoples. It is characterized by the use of raised lugs on the inner face of hull planks. These lugs have holes drilled in them so that other hull components such as ribs, thwarts or other structural components can be tied to them with natural fiber ropes. This allows a structure to be put together without any metal fastenings. The planks are further stitched together edge-to-edge by sewing or using dowels ("treenails") unto a dugout keel and the solid carved wood pieces that form the caps for the prow and stern. Characteristically, the shell of the boat is created first, prior to being lashed unto ribs. The seams between planks are also sealed with absorbent tapa bark and fiber that expands when wet or caulked with resin-based preparations.
Phoenician joints is a locked mortise and tenon wood joinery technique used in shipbuilding to fasten watercraft hulls. The locked mortise and tenon technique consists of cutting a mortise, or socket, into the edges of two planks and fastening them together with a rectangular wooden knob. The assembly is then locked in place by driving a dowel through one or more holes drilled through the mortise side wall and tenon.
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