A
dowel is a solid cylindrical
rodIn geometry, a rod is a three-dimensional, solid cylinder....
, usually made of
woodWood is a hard, fibrous tissue found in many trees. It has been used for hundreds of thousands of years for both fuel and as a construction material. It is an organic material, a natural composite of cellulose fibers embedded in a matrix of lignin which resists compression...
,
plasticA plastic material is any of a wide range of synthetic or semi-synthetic organic solids used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce production costs...
or
metalA metal , is an element, compound, or alloy that is a good conductor of both electricity and heat. Metals are usually malleable and shiny, that is they reflect most of incident light...
. In its original manufactured form, dowel is called
dowel rod.
Dowel rod is employed in numerous, diverse applications. It is used to form
axleAn axle is a central shaft for a rotating wheel or gear. On wheeled vehicles, the axle may be fixed to the wheels, rotating with them, or fixed to its surroundings, with the wheels rotating around the axle. In the former case, bearings or bushings are provided at the mounting points where the axle...
s in toys, as
detentDetent is the term for a method, as well as the actual device, used to mechanically resist or arrest the rotation of a wheel, axle or spindle....
s on
gymnastics gripsGrips are devices that are worn on the hands of artistic gymnasts when performing on various gymnastics apparatus. They are worn by female gymnasts on the uneven bars, and by male gymnasts on the high bar, still rings and parallel bars...
, as knitting needles, as structural reinforcement in
cabinet makingCabinet making is the practice of using various woodworking skills to create cabinets, shelving and furniture.Cabinet making involves techniques such as creating appropriate joints, dados, bevels, chamfers and shelving systems, the use of finishing tools such as routers to create decorative...
and support for tiered wedding cakes. Dowel rod is often cut into short lengths called
dowel pins, which are used in various ways:
- As shelf supports in furniture.
- As moveable pieces (i.e., pegs) in games.
- As supports for hanging items such as key rings, tools, toilet roll dispensers and picture frames.
- To secure two objects together with precise alignment in a dowel joint: a hole is bored in both objects and the dowel pin is inserted into the aligned holes.
- To wind textiles around
- To bear the weight of tiers on stacked cakes.
Wood dowel
Manufacturing process
For modest
manufacturingManufacturing is the use of machines, tools and labor to produce goods for use or sale. The term may refer to a range of human activity, from handicraft to high tech, but is most commonly applied to industrial production, in which raw materials are transformed into finished goods on a large scale...
volumes, wood dowels are typically manufactured on industrial dowel
machineA machine manages power to accomplish a task, examples include, a mechanical system, a computing system, an electronic system, and a molecular machine. In common usage, the meaning is that of a device having parts that perform or assist in performing any type of work...
s. Such machines employ
interchangeableInterchangeable parts are parts that are, for practical purposes, identical. They are made to specifications that ensure that they are so nearly identical that they will fit into any device of the same type. One such part can freely replace another, without any custom fitting...
cutting heads of varying
diameterIn geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints are on the circle. The diameters are the longest chords of the circle...
s, thus enabling the machines to be quickly retooled to manufacture different diameters of dowel (e.g., 1/4", 1/2", 2", etc.). Each head consists of a hollow
chuckA chuck is a specialized type of clamp used to hold an object, usually an object with radial symmetry, especially a cylindrical object. It is most commonly used to hold a rotating tool or a rotating workpiece...
with
cutting knivesThe term tool bit generally refers to a non-rotary cutting tool used in metal lathes, shapers, and planers. Such cutters are also often referred to by the set-phrase name of single-point cutting tool. The cutting edge is ground to suit a particular machining operation and may be resharpened or...
protruding inward, through which the wood passes as the knives cut it into cylindrical shape. The mechanism is open-ended, with material guides at the machine's entry and exit to enable fabrication of continuous dowel rod of unlimited length. Some dowel machines have powered feed devices that automatically feed material into the machine, while others require hand feeding.
High-volume dowel manufacturing is done on a
wood shaperA wood shaper, usually just shaper in North America or spindle moulder in the UK, is a stationary woodworking machine in which a vertically orientated spindle protrudes from the machine table and can be spun at speeds typically between 3000 and 10,000 rpm. Cutter heads may be mounted on the spindle...
, which simultaneously forms multiple dowels from a single piece of rectangular stock (i.e., wood). These machines employ two wide, rotating cutting heads, one above the stock and one below it. The heads have nearly identical cutting
profileIn standardization, a profile consists of an agreed-upon subset and interpretation of a specification. Many complex technical specifications have many optional features, such that two conforming implementations may not inter-operate due to choosing different sets of optional features to support...
s so that each will form an array of adjoined, side-by-side "half dowels". The heads are aligned to each other and one head is shaped to make deeper cuts along the dowel edges so as to part the stock into individual dowel rods, resulting in a group of dowel rods emerging in
parallelParallelism is a term in geometry and in everyday life that refers to a property in Euclidean space of two or more lines or planes, or a combination of these. The assumed existence and properties of parallel lines are the basis of Euclid's parallel postulate. Two lines in a plane that do not...
at the machine's output.
Application
The wooden dowel rod used in
woodworkingWoodworking is the process of building, making or carving something using wood.-History:Along with stone, mud, and animal parts, wood was one of the first materials worked by early humans. Microwear analysis of the Mousterian stone tools used by the Neanderthals show that many were used to work wood...
applications is commonly cut into dowel pins, which are used to reinforce
jointsJoinery is a part of woodworking that involves joining together pieces of wood, to create furniture, structures, toys, and other items. Some wood joints employ fasteners, bindings, or adhesives, while others use only wood elements. The characteristics of wooden joints - strength, flexibility,...
and support shelves and other components in
cabinet makingCabinet making is the practice of using various woodworking skills to create cabinets, shelving and furniture.Cabinet making involves techniques such as creating appropriate joints, dados, bevels, chamfers and shelving systems, the use of finishing tools such as routers to create decorative...
. Some woodworkers make their own dowel pins, while others purchase dowel pins precut to the required length and diameter. Various systems, such as
DowelmaxThe Dowelmax is a loose tenon dowelling jig manufactured by the O.M.S. Tool company in Canada. The manufacturer claims that the small manufacturing tolerances of for the aluminium, brass and steel components of the jig ensure accuracy and repeatability...
, have been devised to aid in dowel
joineryJoinery is a part of woodworking that involves joining together pieces of wood, to create furniture, structures, toys, and other items. Some wood joints employ fasteners, bindings, or adhesives, while others use only wood elements. The characteristics of wooden joints - strength, flexibility,...
.
Dowel-based joinery typically employs
fluted dowel pins. A fluted dowel pin has a series of parallel grooves cut along its length. The fluting provides channels through which excess glue—which is used to secure the dowel pin in its hole—can escape as the dowel is inserted, thereby relieving the hydraulic pressure that might otherwise split the timber when the mating pieces are clamped together.
Depending on the application, alternative joinery methods may be used in place of conventional dowel pins, including Miller dowels,
biscuit joinerA biscuit joiner or sometimes plate joiner is a woodworking tool used to join two pieces of wood together. A biscuit joiner uses a small tungsten carbide tipped, circular saw blade to cut a crescent shaped hole in the opposite edges of two pieces of wood or wood composite panels...
s, and proprietary tools such as the
Domino jointerThe Domino is a loose mortise and tenon joining tool manufactured by the German company Festool.-History and description:This tool, first on sale in 2006, cuts mortises in the manner of a biscuit joiner. Each plunge creates a mortise that is sized to accept a Domino loose tenon, creating joints in...
.
In stonemasonry
Steel dowels are commonly used in
masonryMasonry is the building of structures from individual units laid in and bound together by mortar; the term masonry can also refer to the units themselves. The common materials of masonry construction are brick, stone, marble, granite, travertine, limestone; concrete block, glass block, stucco, and...
to pin stone components together. Holes are bored in the stone and the steel dowels inserted to secure the components.
In machinery
Dowel pins are often used as precise locating devices in machinery. Steel dowel pins are
machinedConventional machining is a form of subtractive manufacturing, in which a collection of material-working processes utilizing power-driven machine tools, such as saws, lathes, milling machines, and drill presses, are used with a sharp cutting tool to physical remove material to achieve a desired...
to tight tolerances, as are the corresponding holes, which are typically reamed. A dowel pin may have a smaller diameter than its hole so that it freely slips in, or a larger diameter so that it must be pressed into its hole.
When designing mechanical components, engineers typically use dowel holes as reference points to control positioning variations and attain repeatable assembly quality. If no dowels are used for alignment (e.g., components are mated by bolts only), there can be significant variation, or "play", in component alignment.
Typical drilling and milling operations, as well as manufacturing practices for bolt threads, introduce mechanical play proportional to the size of the fasteners. For example, bolts up to 10mm (3/8") in diameter typically have play on the order of 0.2 mm (0.008 inches). When dowels are used in addition to bolts, however, the tighter dimensional tolerances of dowels and their mating holes—typically 0.01 mm (0.0008")—result in significantly less play, on the order of 0.02 mm (0.0004 inches). Manufacturing costs are inversely proportional to mechanical tolerances and, as a result, engineers must balance the need for mechanical precision against cost as well as other factors such as manufacturability and serviceability.
In automobiles, dowels are used when precise mating alignment is required, such as in differential gear casings, engines, and transmissions.
In woodworking
A
cross dowel is a cylindrically shaped metal nut (i.e., a metal dowel) that is used to join two pieces of wood. Like other metal nuts, it has an inside threaded hole, although the hole is unusual in that it passes through the sides of the dowel. One or both ends of the dowel are slotted, with the slots oriented parallel to the threaded hole through which the bolt will pass.
In a cross dowel application, the two pieces of wood are aligned and a bolt hole is drilled through one piece of wood and into the other. A dowel hole is drilled laterally across the bolt hole and the cross dowel is inserted into it. A screwdriver is inserted into the slot at the end of the cross dowel and the dowel is rotated so that its threaded hole aligns with the bolt hole. The bolt is then inserted into the bolt hole and screwed into the cross dowel until the wood pieces are held tightly together.
See also
- Bar stock
Bar stock, also colloquially known as billet, is a common form of raw purified metal, used by industry to manufacture metal parts and products....
- Dowel reinforced butt joint
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...
- Rebar
A rebar , also known as reinforcing steel, reinforcement steel, rerod, or a deformed bar, is a common steel bar, and is commonly used as a tensioning device in reinforced concrete and reinforced masonry structures holding the concrete in compression...
- Spring pin
A spring pin is a mechanical fastener that secures the position of two or more parts of a machine relative to each other...