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 and as structural reinforcement in cabinet making. 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 keyrings and tools.
- 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.
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 at least 0.2 mm (0.008 inches) play for bolts up to 10 mm (3/8 inches). If dowels are used in addition to bolts, the play is reduced to approximately 0.01 mm (0.0004 inches).[citation needed].
In automobiles, dowels are used when precise mating alignment is required, such as in differential gear casings, engines, and transmissions.
Processing...
