Procedure

1. No ornamental, artistic or cursive style of letters are used in Engineering Drawing.
2. Letters should be distinguishable from each other in order to avoid any confusion even in case of slight mutilations.
3. According to the Bureau of Indian Standards, lettering type 'A' capital letters is divided into 14 parts and lettering type 'B' capital letters is divided into 10 parts.
4. Inclined letters lean to the right being 75 degrees to the horizontal.
5. Background area between letters should be approximately equal.
6. Individual words should be clearly separated by space equal to width of the letter.
7. Space between two numerals with a decimal point between. Minimum two-thirds the lettering height.
8. Vertical space between lines of lettering. Not more than the lettering height, and not less than half the lettering height.
9. The height-to-width ratio for letters varies between 7:5 or 7:6.
10. Lettering with fractions, height of numerator and denominator is equal to 3/4 height of non-fractioned number.
11. Spacing between division bar and numerator or denominator should be such that the total height of fraction will be twice of that of non-fractioned number.
12. Lettering with powers, the height of index is half of height of a base letter.
13. The central horizontal strokes of the letters B, E, F and H are drawn slightly above the centre while top is drawn slightly smaller than bottom.
14. The main titles are written in 6 mm to 8 mm size while the sub-titles are written in 3 mm to 6 mm size.
15. Notes and dimension figures are written in 3 mm to 5 mm size.