Lettering

In the context of engineering drawing, the writing practices of titles, dimensions, notes, and other critical information on a drawing sheet is known as lettering. This element is crucial to the overall quality of the engineering drawing. Regardless of how precise and neatly the drawing is executed, poor lettering can diminish its visual appeal and intricacy, more importantly, compromise its effectiveness. Therefore, the knowledge of lettering is essential. Efficiency in the art of lettering can be achieved through careful and continuous practice. As the use of drawing instruments in lettering takes considerable time and should be avoided, instead it should be done in a clear, legible, and consistent manner, using a straightforward style that can be executed freehand with speed and accuracy.

There are two types of letters in engineering is predominantly used:

1. Single-stroke letters
2. Gothic letters

For engineering drawing students, developing proficiency in proper lettering is not just about aesthetics but also about ensuring that the technical information conveyed is unambiguous and accessible. In this module, we will be focusing on the Single-stroke letters technique.

Single Stroke letters

Most often Single Stroke letters are used in engineering and The Bureau of Indian Standards (IS:9609-2001) recommends single-stroke lettering for use in engineering drawing. The term "single-stroke" should not be misunderstood as requiring the entire letter to be drawn in a single motion without lifting the pencil. Instead, it refers to the uniform thickness of the letter's lines, achieved with a single stroke of the pencil. When forming letters, horizontal lines should be drawn from left to right, while vertical or inclined lines should be drawn from top to bottom. Practicing and proficient in the technique is essential for producing clear and standard drawings. Single-stroke lettering is classified into two types:

1. Vertical
2. Inclined

Both styles are fundamental in engineering drawings, where precision and clarity are paramount, ensuring that technical information is easily readable and accurately communicated. Inclined letters lean to the right, the slope being 75° with the horizontal.

The size of a letter is described by its height. In engineering drawing, certain standards and rules must be followed to ensure consistency. Different sizes of letters are utilized depending on their purpose within the drawing.

1. Main Titles: Typically written in a size ranging from 6 mm to 8 mm.

2. Sub-Titles: Usually in the range of 3 mm to 6 mm.

3. Notes, Dimension Figures, and Other Annotations: Generally written in sizes between 3 mm and 5 mm.

4. Drawing Number in the Title Block: Written in numerals that are 10 mm to 12 mm in size.

These size variations help differentiate between different elements of the drawing, making it easier to read and interpret.

There are some important points one should keep in mind while lettering:

1. All letters should be uniform in shape, slope, size, shade and spacing throughout the drawing. For maintaining uniformity in size, thin and light guide-lines may first be drawn, and lettering may then be done between them (As shown in the simulation).
2. The shade of every letter must be the same as that of the outlines of drawings, i.e. intensely black. The shade of every letter must be the same as that of the outlines of drawings, i.e. intensely black.
3. The spacing between letters doesn’t need to be uniform, but it should be adjusted so that the letters neither appear too close nor too far apart. The gaps between letters should look visually balanced (judging by eyes), with background areas kept roughly equal. The spacing between words should be consistent and at least equal to the height of the letters.
4. Lettering should be so done as can be read from the front with the main title horizontal, i.e. when the drawing is viewed from the bottom edge.
5. All sub-titles should be placed below but not too close to the respective views. Lettering, except the dimension figures, should be underlined to make them more prominent.