List General Rules for Dimensioning – A neat drawing is not only required to achieve full marks in technical drawing but several rules for dimensioning must be followed.
The following rules should be considered while dimensioning:
1. Standard sizes of letters and figures should be used.
2. All dimensions should be specified in mm. The use of mm should be avoided by giving a general note “All dimensions are in mm”.
3. As far as possible dimensions should be placed outside the views.
4. Dimension lines should not run in the direction included in the hatched area.
5. Dimensions should be taken from visible outlines rather than from dashed lines.
6. Dimensions should be given from a base line, a centre line, an important hole, or a finished surface which may be readily established.
7. Dimensions should be quoted only once in one view.
8. Overall dimensions should be placed outside the intermediate dimensions.
9. Dimensions should be placed outside a sectional view.
10. Zero should precede the decimal point when the dimension is less than unity.
11. Dimension line should not cross. Also dimension lines and extension lines should not cross.
12. When there are several dimension lines, the shorter dimension should be nearer the view.
13. Leaders should not be drawn curved or made free hand.
14. Do not use outlines for dimensions.
15. Same method of dimensioning should be used for all dimension lines.
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