Dowel


Dowel

A dowel is a solid cylindrical rod, usually made of wood, plastic or metal. In its original manufactured form, dowel is called dowel rod.

Dowel rod is employed in numerous, diverse applications. It is used to form axles in toys, as detents on gymnastics grips, as knitting needles, as structural reinforcement in cabinet making 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.

Contents

Wood dowel

Fluted wood dowel pin
Dowel joint
A steel dowel
Cross dowel. Note that the slot is usually parallel to the bolt hole, contrary to this drawing.
A cutaway view of a cross dowel in use. For illustrative purposes the dowel's slot is shown perpendicular to the bolt, but in practice the slot is usually parallel to the bolt.

Manufacturing process

For modest manufacturing volumes, wood dowels are typically manufactured on industrial dowel machines. Such machines employ interchangeable cutting heads of varying diameters, 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 chuck with cutting knives 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 shaper, 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 profiles 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 parallel at the machine's output.

Application

The wooden dowel rod used in woodworking applications is commonly cut into dowel pins, which are used to reinforce joints and support shelves and other components in cabinet making. Some woodworkers make their own dowel pins, while others purchase dowel pins precut to the required length and diameter. Various systems, such as Dowelmax, have been devised to aid in dowel joinery.

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 joiners, and proprietary tools such as the Domino jointer.

Metal dowel

In stonemasonry

Steel dowels are commonly used in masonry to pin stone components together. Holes are bored in the stone and the steel dowels inserted to secure the components.

In machinery

Steel dowel pins

Dowel pins are often used as precise locating devices in machinery. Steel dowel pins are machined 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).[citation needed] 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).[citation needed] 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

References


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Synonyms:

Look at other dictionaries:

  • Dowel — Dow el, n. [Cf. G. d[ o]bel peg, F. douelle state of a cask, surface of an arch, douille socket, little pipe, cartridge.] (Mech.) 1. A pin, or block, of wood or metal, fitting into holes in the abutting portions of two pieces, and being partly in …   The Collaborative International Dictionary of English

  • dowel — ► NOUN ▪ a headless peg used for holding together components. ► VERB (dowelled, dowelling; US doweled, doweling) ▪ fasten with a dowel. ORIGIN perhaps Low German …   English terms dictionary

  • Dowel — Dow el, v. t. [imp. & p. p. {Doweled}or {Dowelled}; p. pr. & vb. n. {Doweling} or {Dowelling}.] To fasten together by dowels; to furnish with dowels; as, a cooper dowels pieces for the head of a cask. [1913 Webster] …   The Collaborative International Dictionary of English

  • dowel — mid 14c., dule rim or section of a wheel, perhaps akin to M.L.G. dovel plug, tap (of a cask). Modern meaning is first attested 1794 …   Etymology dictionary

  • dowel — [dou′əl] n. [ME doule, prob. akin to MLowG dövel, Ger döbel, a plug < IE base * dheubh , a peg, wooden pin > DUB1] a short cylinder of wood, metal, etc., usually fitted into corresponding holes in two pieces to fasten them together vt.… …   English World dictionary

  • dowel — /dow euhl/, n., v., doweled, doweling or (esp. Brit.) dowelled, dowelling. n. 1. Also called dowel pin. Carpentry. a pin, usually round, fitting into holes in two adjacent pieces to prevent their slipping or to align them. 2. a piece of wood… …   Universalium

  • dowel — UK [ˈdaʊəl] / US noun [countable] Word forms dowel : singular dowel plural dowels a thick pin made of wood, metal, or plastic, used for holding two pieces of wood, metal, or plastic together …   English dictionary

  • dowel — [[t]da͟ʊəl[/t]] dowels N COUNT A dowel is a short thin piece of wood or metal which is used for joining larger pieces of wood or metal together …   English dictionary

  • dowel — [ daʊəl] noun a headless peg used for holding together components. verb (dowels, dowelling, dowelled; US dowels, doweling, doweled) fasten with a dowel. Origin ME: perh. from Mid. Low Ger. dovel …   English new terms dictionary

  • dowel — /ˈdaʊəl / (say dowuhl) Carpentry –noun 1. Also, dowel pin. a pin, usually round, fitting into corresponding holes in two adjacent pieces to prevent slipping or to align the two pieces. 2. Also, dowelling. long, thin, round strips of wood suitable …   Australian English dictionary