Engineering drawing requires precision and accuracy, and for this, various drawing instruments are used. These instruments help in creating detailed and standardized drawings essential for design, manufacturing, and construction. Some commonly used drawing instruments include:

• Drawing board
  
  

• Drawing paper and tapes/pins/clips
  
  

• Pencils
  
  

• T-square
  
  

• Set square
  
  

• Scale (ruler)
  
  

• Drafter
  
  

• Protractor
  
  

• Roller scale
  
  

• French curves
  
  

• Compass
  
  

• Eraser

1. Drawing Board

• Rectangular in shape and made of wood (about 25mm thick).
  
  

• It is cleated at the back with two battens to prevent warping.
  
  

• The board should have a smooth surface for drawing.
  
  

• It has a working edge that helps in aligning instruments like the T-square.
  
  

2. Drawing Paper

• Available in different sizes such as A0, A1, A2, A3, and A4.
  
  

• Should be slightly smaller than the drawing board for proper fitting.
  
  

• Fixed using drawing pins, clips, or tape.
  
  

3. Pencils

• Used for different types of lines in technical drawings.
  
  

• The quality of pencils affects the accuracy and appearance of drawings.
  
  

• Common grades:
  
  

  • H (Hard) & 2H – Used for construction and light lines.
    
    

  • HB – Used for general drawing and outlines.
    
    

  • B (Soft) – Used for dark, bold lines and shading.

4. T-Square

• Consists of two parts: Stock and Blade joined at right angles.
  
  

• Used for drawing horizontal straight lines.
  
  

• It slides along the working edge of the drawing board for accuracy.
  
  

5. Set Squares

• Triangular instruments used for drawing angles.
  
  

• Two common types:
  
  

  • 45°-45°-90°
    
    

  • 30°-60°-90°
    
    

• Used in combination with the T-square to draw vertical and inclined lines.
  
  

6. Scale (Ruler)

• Used for measuring and drawing straight lines of specific lengths.
  
  

• Available in different units such as millimeters (mm), centimeters (cm), and inches.
  
  

• Engineering scales are used for technical drawings with different ratios like 1:10, 1:100, etc.
  
  

7. Protractor

• A semi-circular instrument used to measure and draw angles.
  
  

• Marked from 0° to 180° with 1° divisions.
  
  

• Some advanced protractors can measure angles up to 360°.
  
  

8. Drafter (Drafting Machine)

• A combination of a T-square, set square, scale, and protractor.
  
  

• One end is clamped to the drawing board, and the other end is adjustable.
  
  

• Allows for precise movement and drawing of parallel lines, angles, and arcs.
  
  

9. Roller Scale

• Has a built-in roller for smooth movement.
  
  

• Used for drawing vertical, horizontal, parallel lines, and circles with precision.
  
  

10. French Curves

• Used for drawing smooth curves that cannot be drawn using a compass.
  
  

• Helps in creating ellipses, parabolas, hyperbolas, and irregular curves.
  
  

• Comes in various shapes for different curve designs.
  
  

11. Compass

• Used for drawing circles and arcs of specific radii.
  
  

• Can be fitted with different lead grades for varying line thicknesses.
  
  

• Extension bars can be added for larger circles.
  
  

12. Eraser

• Used to remove pencil marks without damaging the drawing paper.
  
  

• Should be soft to avoid roughening the paper surface.
  
  

• A kneaded eraser is preferred for fine adjustments and lightening lines without erasing completely.
  
  

Additional Tips for Engineering Drawing:

• Keep drawing instruments clean and in good condition for accurate results.
  
  

• Use a sharpened pencil for precise lines.
  
  

• Maintain a light hand while sketching guidelines.
  
  

• Always check measurements twice before finalizing.
  
  

• Store instruments properly to prevent damage.