Parallels (engineering) - Description

Description

Parallels come in pairs of two, which are machined to be the same dimensions their corresponding faces. They come in a variety of thicknesses and size, allowing them to be stacked up or to support a workpiece which doesn't have a flat profile. Parallels commonly have a series of holes drilled on the 'front' face - allowing them to be used to position a workpiece or secured using t-slot clamps, and a countersink on each side to remove any sharp edges.

Generally, workshop parallels have 4 faces that are machined and ground - the front, back and sides, although some do have the ends with a smooth surface. The surface of a parallel can often tell how it was manufactured, with a 'grain' showing that it was ground - and a smooth or mirrored finish showing it has been lapped. Parallels that have a good surface tolerance can be lightly bonded together by sliding or rotating two parallels together, and the smooth surfaces allows a temporary molecular-attraction to take place - this is known as Wringing and is also found with gauge blocks.

Read more about this topic:  Parallels (engineering)

Famous quotes containing the word description:

    It [Egypt] has more wonders in it than any other country in the world and provides more works that defy description than any other place.
    Herodotus (c. 484–424 B.C.)

    A sound mind in a sound body, is a short, but full description of a happy state in this World: he that has these two, has little more to wish for; and he that wants either of them, will be little the better for anything else.
    John Locke (1632–1704)

    Do not require a description of the countries towards which you sail. The description does not describe them to you, and to- morrow you arrive there, and know them by inhabiting them.
    Ralph Waldo Emerson (1803–1882)