Technical Drawing: Essential Tools, Materials, and Techniques

Posted on Jan 7, 2025 in Technology

Technical Drawing: Essential Tools, Materials, and Techniques

Instruments

Instruments are composite objects for one or more pieces combined with each other that help when performing a path.

  • Ruler: An instrument comprising a scale with graduated numbering (cm or mm). Its use is to draw lines and measure.
  • T-Square: An instrument made of two parts (leaf and head). Its function is a horizontal support for other instruments and serves to draw parallel lines.
  • Squares: These are triangular instruments used for vertical layout.
    • Isosceles: 45º, 45º, 90º
    • Scalene: 30º, 60º, 90º
  • Protractor: A circular section tool used to obtain angles.
  • Compass: An instrument that serves to draw curved lines.
    • Bow Compass: Designed to draw small arcs or circles.
    • Divider: Used for taking or transferring measurements.
    • Replacement Compass
    • Beam Compass

Materials

To get good results in technical drawing, good quality materials are needed.

  • Pencil: Pencils used in technical drawings have special features and respond specifically to the function required.
    • Soft Strokes: All Series B (7B to B)
    • Medium Strokes: HB, F
    • Hard Strokes: All Series H (H to 7H)
  • Paper: Good presentation and finish of a design depend largely on the quality of paper used.
    • Opaque: It is usually white, with variations in thickness. The drawing surface is generally smooth and shiny.
    • Translucent: It is more often used in technical drawing, allowing for layers and excellent copies in plan reproduction machines.
  • Tape: It serves to support the paper on the table and set it to avoid errors in the drawing.
  • India Ink: It is a quite dense liquid whose components make it indelible, resistant to weather and humidity.
  • Erasers: Abrasive materials are designed to eliminate pencil traces.

Format

The format is the standard box according to its length and width dimensions where all technical drawings are made.

DIN Series

The formats of the series A are the most used and can be seen in all sizes, from independent roles such as design statements, postcards, printed patterns, letter leaves, ads, etc. DIN standards require that all forms must be:

  • Geometrically similar to each other.
  • Rectangular in shape.
  • Measured in millimeters.

Scales

It is the ratio between a real object and a drawn one.

  • Matching: Real Object = Drawn Object
  • Expansion: Real Object < Drawn Object
  • Reduction: Real Object > Drawn Object

Scale Ruler

It is a very versatile instrument that serves only to measure, though it offers 6 scales (1:125 / 1:100 / 1:75 / 1:50 / 1:25 / 1:20).

Scale and Sub-Scale Relationships

  • Smaller Stroke = More Zeros
  • Larger Stroke = Fewer Zeros

Lettering

It is the art of writing letters, numbers, and signs in accordance with established rules.

  • DIN 16: It is drawn at an angle between 40 and 75 degrees.
  • DIN 17: It is drawn at 90 degrees.

Letter Width = X = 0.4 cm
Height of the Letter = Y = 0.5 cm
Letter Separation = Sx = X / 4 = 0.1 cm
Word Separation = Sp = Sx * 3 = 0.3 cm
Line Separation = Equal to Y = 0.5 cm