Lettering Information

Technology Education Department
Introduction to Technical Drawing

LETTERING

"Lettering" on a drawing enables the engineer, architect or designer to communicate a complete description of an object. The tradesperson, that will make the object, and the client, that will buy the object, must be able to look at and read the plans. A drawing without "lettering" would only communicate the appearance and shape of an object. The size (length, width and height) of the object, the location of features (holes and cutouts), and the materials needed to make the object can only be expressed by words which must be "lettered" in a clear and uniform style.

The American National Standards Institute (ANSI) has designated the Gothic alphabet as the standard style of lettering for engineering and architectural drawings. Engineers and designers use single-stroke, vertical letters on their drawings (single stroke vertical Gothic). Architects use a stylized form of Gothic lettering for titles and cover pages. CAD systems have decreased the importance of lettering skills for CAD operators; but most of the information that is exchanged between engineers, designers and architects and the drafter or CAD operator is through freehand sketches with hand lettered information. The ability to "letter" a drawing or sketch in a neat and consistent style is an important skill for success in the design and drafting profession. The spacing of letters and words uniformily is called "composition". Always use very light guidelines when lettering to control the height of the letters and to keep letters in a straight line.

RULES FOR LETTERING

USE THE SINGLE-STROKE, VERTICAL, GOTHIC STYLE OF LETTERING.
USE UPPER CASE (CAPITAL) LETTERS ONLY!
ALWAYS SKIP A SPACE BETWEEN ROWS OF LETTERS.
ALWAYS USE VERY LIGHT GUIDE LINES.
NORMAL LETTERING IS MADE 1/8" OR 3 mm HIGH.
TITLES SHOULD BE LETTERED 1/4" OR 6 mm HIGH.
FRACTIONS ARE LETTERED TWICE THE HEIGHT OF NORMAL LETTERS.
FRACTION BARS ARE ALWAYS DRAWN HORIZONTAL.
USE A MEDIUM (B, HB, F OR H) LEAD FOR NORMAL LETTERING.
USE A HARD (4H TO 9H) LEAD FOR DRAWING GUIDE LINES.

Lettering is added to a drawing to complete the description of the object. A drawing with pictures and views shows only what an object looks like. The name, material, color and size of an object must be given in the form of words, notes and numbers.
Drafters, designers, engineers, architects and technicians must have neat uniform "freehand" lettering skills in order to communicate accurate information about a product to each other as well as to the carpenters, electricians, plumbers, machinists, welders and other tradespersons that will have to manufacture the product. The ability to space letters and words uniformily is called "composition".
The ANSI (American National Standards Institute) style of lettering used on technical drawings is called Single-stroke Vertical Gothic. Single-stroke means the letters are formed by following a prescribed series of vertical, horizontal, angular and curved strokes as you make each letter. Vertical means the letters are perpendicular to the guide lines not slanting forward or backward. This is the same style you learned to print in elementary school.
Architects will sometimes "personalize" the Gothic lettering style to distinguish their work from others. These personalized letters are used primarily for drawing titles and on cover pages.
Guide lines are very light horizontal lines used to keep letters a uniform height and parallel to the edges of the paper. Multiple lines of lettering should be uniformily space and separated by a blank space. A sharp pointed, hard (4H to 6H) weight lead or drawing pencil is best for drawing guide lines.
Only upper case (capital) letters should be used since most lettering is only 1/8th of an inch high. Titles can be made 1/4th of an inch high or a combination of 1/4th and 1/8th of an inch letters. When using fractions, the bar should be horizontal in the middle of the space with numerator and denominator extending halfway into the space above and below the line of text. A round pointed, medium (H or HB) weight lead or drawing pencil is best for doing lettering.
The Computer Aided Drawing (CAD) software has a variety of type fonts available for professional looking lettering. Wordprocessing software can be used to create title block and cover pages.