In this short article, we will certainly learn around what is Dimensions and also types of Dimensioning systems supplied in Engineering Drawings.

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Dimensions and Dimensioning Systems

A Dimension is a numerical worth expressed in appropriate units of measurement and used to define the dimension, place, orientation, form or other geometric attributes of a component. In other words, indicating on a illustration, the sizes of the object and the other details crucial for its building and also feature using lines, numerals, icons, notes, etc., is referred to as dimensioning.To construct an object its shape and size have to be well-known. Thus, an design illustration, depicting the form, size and pertinent details a lot of vital for the building of the object. The dimensions are offered to indicate the sizes of the assorted features of the object and also their place. It is greatly used to understand the object dimension, the name of parts and also diameter of the hole and so on.Read Also – 10 Different Types of Lines Used In Engineering DrawingWhat you’ll learn in this post:Elements of DimensioningUnits of DimensionsDimensioning common featuresTypes of Dimensioning SystemsType of Dimensioning

1. Elements of Dimensioning

It contains projection line, leader line, termicountry of the measurement line, the beginning indication, icons and also the dimension itself.Dimension Line: Dimension line is a consistent thin line. it is shown by arrowheads, it is attracted parallel to the surconfront whose size need to be suggested.

Projection or Extension Line: A estimate line or extension line, it is a thin line. It is drawn perpendicular to the surface which is to be dimensioned. The estimate line slightly extends than the measurement line.

Constructions line: A building and construction line is a thin line drawn to suggest the dimension line. The building line is extfinished slightly beyond the suggest interarea.Arrowheads: Arrowheads are provided to suggest the dimension line. Usually, the arrowhead should include angles of a minimum of 15°. The Arrowhead might be open up or cshed or closed and also filled.

Leader or Pointer Lines: These are thin constant lines attracted from a dimension number to the attribute to which it refers. Leader line is attracted might be 30° or 60° to the bottom of dimensions.Dimension Figure: These are attracted might be vertical or inclined to show the elevation of the measurement number.

2. Units of Dimensions

The measurement unit is millimetre. The unit of the measurement is omitted while writing the dimension fig. and a footnote stating “ALL DIMENSIONS ARE IN MM” is created at the prominent place on the drawing sheet.

3. Dimensioning prevalent features

Dimensioning diameters


Circular features favor cylindrical parts like shafts, pipes, rods or any other round shape are constantly dimensioned by indicating their diameter. Due to the fact that it is quickly measured.

The diameter is suggested by the symbol ∅. The diameters on the circular objects may be suggested in any type of one of the adhering to methods as presented in fig.

Dimensioning Radius

The curved, fillets and round figures are presented in drawings by arcs or circles. The dimensioning is done by offering radii.
The measured radius is indicated by letter R. The measurement line is drawn radial with the arrowhead emotional the arc.When the centre is situated by the projection lines, the centre shall be noted by a clear dot and the arrowhead may be reversed.When the centre of the arc falls outside the illustration limit, the measurement line of the radius must be damaged or interrupted according to whether or not it situated the centres.

Dimensioning Arcs

When dimensioning the length of an arc the dimension number identified by symbol being composed above the dimension.

Dimensioning Chords

It is a direct distance between any 2 points of an arc. And it is dimensioned as shown in the figure.

Dimensioning Angles

The angles are dimensioned in the exact same manner as that of straight dimensions.

4. Types of Dimensioning systems:

Tbelow are 2 types of dimensioning systems one is Aligned device and one more is Unidirectional mechanism.

Aligned System

In this type of dimensioning units, Dimensions are inserted over the measurement lines which are attracted without any break and also written parallel to them.That they might be review from the bottom or any kind of various other side of the drawing sheet. Dimensions are placed in the middle and also on height of the measurement lines.

Unidirectional System

In this form of dimensioning mechanism, dimensions are placed in such a way that they deserve to be read from the bottom edge of the drawing sheet. Dimensions are inserts by breaking the dimension lines at the middle.

Dimensions need to be attracted favor this

Use only one placing of dimension mechanism in one entire illustration. The aligned and unidirectional mechanism must not be combined together in one illustration.

5. Types of Dimensioning

The different techniques, setup and the indication of measurement areChain DimensioningParallel DimensioningIntegrated DimensioningProgressive DimensioningDimensioning by Co-ordinatesEquidistant DimensioningRepeated Dimensions

Chain Dimensions

Chain dimensioning is a dimensioning system that dimensions from suggest to allude. Or it is a series of adjacent dimensions are arranged in one horizontal row. When chain dimensioning is used the location of one feature is based upon the area of the previous attribute from which it is dimensioned.Chain dimensioning is provided when it is crucial that 2 functions are located at a specific distance from each other. For instance, Two addressed holes with two addressed pins may need a specific distance from each other to draw chain dimensions.

Parallel Dimensioning

When the variety of dimensions is measured in the exact same direction from a prevalent surchallenge or line. The method of indicating all the dimensions from the same function is called parallel dimensioning. The dimension lines are parallel to each various other and equally spaced.

Combined Dimensioning

In this approach, both the chain and parallel dimensions are supplied in the very same illustration.

Progressive Dimensioning

This strategy is embraced when dimension has to be established from a particular datum. The overall dimensions are placed external the smaller sized dimensions this measurement is showed by the prevalent reference line.

Dimensioning by Coordinates

Dimensioning by a coordinate table have the right to be used in location of various other dimensioning layouts. This have the right to make illustration easier to review, this strategy is done when a variety of holes of various sizes have to be dimensioned.

Equiremote Dimensioning

The dimensioning simplified by provided the product of the number of spacing and also the measurement worth. A point is said to be equiremote from a set of objects if the distance becomes that points and also each object in the set are equal.

Repeated Dimensions

When particular attributes or elements of the exact same dimension are repetitive a variety of times on drawing, to prevent repetition of the same dimension everywhere, the product of a number of repetitive attributes and also the dimensions worth may be shown just at one such feature.

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Dimensions are incredibly essential in the design area and also it is the a lot of useful ability in an sector that will aid you to read any type of engineering drawing without any type of confusion. Learning and understanding of exactly how dimensions are discussed are extremely simple if you focus on discovering.Download PDF of this article
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Saif M. is a Mechanical Engineer by profession. He completed his design research studies in 2014 and also is currently working in a large firm as Mechanical Engineer. He is also an writer and also editor at