5.1 Technical drawing tools and equipment

5.1.1 Drawing board

Drawing boards are the foundation of manual architectural drafting, providing a reliable surface that ensures stability and precision during the drawing process. Kenyan architectural firms and training institutions emphasize quality drawing boards to support professional presentation and accuracy.

Specifications and materials

• Dimensions: Standard drawing boards measure approximately 60 cm by 90 cm, offering ample space for A2 or A3-sized sheets commonly used in architectural drawings.
• Surface: The board surface must be smooth and flat to prevent paper distortion or uneven lines. Materials such as plywood or MDF coated with melamine are common.
• Edges: Some boards have beveled or rounded edges to prevent damage to paper sheets and to facilitate comfortable hand movement.
• Parallel motion ruler compatibility: Boards often include mounts or grooves to attach parallel rulers for drawing straight lines.
• Portability features: Lightweight yet sturdy boards may include handles or clips for ease of transport between site offices and studios.

Uses in architectural drawing

• Provides a flat, stable base essential for precise line work and measurements.
• Supports attachment of paper sheets using clips or drafting tape to prevent movement during drawing.
• Allows the use of other tools such as T squares and set squares in alignment with the board edges.
• Facilitates the use of parallel rulers for drawing horizontal lines across the sheet.
• Serves as a consistent platform for repetitive tasks like tracing or overlaying drawings.

Maintenance and care

• Regularly clean the surface with a soft cloth to remove dust and debris that can cause uneven drawing lines.
• Avoid exposure to moisture which can warp wooden boards.
• Store vertically or flat in a dry environment to maintain flatness.
• Check and tighten any attachments or clips to ensure secure holding of drawing sheets.
• Replace worn or damaged boards to maintain drawing precision.

5.1.2 Set square

Set squares are essential for creating accurate perpendicular and angled lines, fundamental in architectural drafting to depict walls, roofs, and other structural elements precisely.

Types and specifications

• 45°-45°-90° set square: Used for drawing right angles and 45-degree lines, common in orthogonal projections.
• 30°-60°-90° set square: Enables drawing of 30, 60, and 90-degree angles, useful for isometric and axonometric drawings.
• Material: Typically made from transparent acrylic or plastic to allow visibility of underlying drawing lines.
• Size: Commonly 15 cm or 30 cm edges for ease of handling and precision.
• Graduations: Some set squares include measurement markings to assist in scaling and dimensioning.

Uses in architectural drawings

• Drawing vertical and angled lines with precision, crucial for floor plans and elevations.
• Checking and reinforcing perpendicularity between lines and elements.
• Facilitating the creation of geometric shapes and patterns within architectural detailing.
• Assisting in the layout of orthographic projections and sectional views.
• Providing a guide for lettering aligned with architectural drawing standards.

Handling and maintenance

• Store in protective cases or holders to prevent warping or chipping.
• Clean with a soft cloth to remove smudges that could obscure visibility.
• Avoid bending or dropping, which can compromise angle accuracy.
• Inspect edges regularly to ensure they remain straight and true.
• Replace if transparency fades or if the square is damaged.

5.1.3 Compasses

Compasses are vital for architects when drawing circles, arcs, and curves essential in plans, sections, and detail drawings, such as curved windows, arches, or landscaping elements.

Types and specifications

• Bow compass: Features a screw mechanism for fine adjustment, allowing precise radius control.
• Beam compass: Used for drawing larger circles beyond the capacity of standard compasses, often adjustable with a sliding arm.
• Needle point: Secures the pivot on the drawing surface to prevent slipping.
• Pencil holder: Holds pencils or technical pens for consistent line thickness.
• Material: Typically made of metal for durability and stability.

Uses in architectural drawings

• Drawing accurate circles representing columns, circular windows, and other curved elements.
• Creating arcs for detailing roof slopes, staircases, and landscaping curves.
• Marking radii for chamfers or fillets in detailed drawings.
• Assisting in the construction of geometric patterns and motifs.
• Facilitating dimensioning by marking arcs corresponding to measured distances.

Care and maintenance

• Keep pivot points sharp and clean to prevent slipping and inaccuracies.
• Lubricate adjustment screws lightly to maintain smooth movement.
• Store in a protective case to avoid bending or damage to arms.
• Regularly check the pencil holder for tightness and replace worn pencils.
• Avoid dropping or rough handling that could misalign the instrument.

5.1.4 T square

The T square is a fundamental tool for architects, providing a straight edge for drawing horizontal lines and aligning other drawing instruments on the board.

Specifications and design

• Length: Typically ranges from 45 cm to 90 cm to accommodate different paper sizes.
• Head: The crosspiece or head is perpendicular to the blade, allowing it to rest firmly against the drawing board edge.
• Material: Made from wood, plastic, or metal, balancing durability and weight.
• Edge: The blade edge is finely machined to ensure straightness.
• Graduations: Some T squares have measurement markings on the blade for quick dimensioning.

Uses in architectural drawing

• Drawing horizontal lines across the paper with consistent straightness.
• Aligning set squares to draw vertical or angled lines accurately.
• Serving as a guide for lettering and dimensioning parallel to the baseline.
• Assisting in the layout of gridlines and modular design elements.
• Providing stability when drawing repetitive parallel lines.

Maintenance and handling

• Store vertically or hung to prevent warping of the blade.
• Clean regularly to remove graphite or ink build-up.
• Avoid exposure to extreme temperatures which can warp plastic or wooden T squares.
• Inspect the perpendicularity of the head to the blade periodically.
• Replace if the blade edge becomes chipped or uneven.

5.1.5 French curve

The French curve is an essential tool for architects when drawing smooth, irregular curves that cannot be constructed with compasses or set squares.

Specifications and types

• Material: Typically made from transparent plastic or acrylic for visibility.
• Shape: Contains multiple curved edges with varying radii to accommodate different curve requirements.
• Size: Usually about 15 to 30 cm in length to fit comfortably on drawing sheets.
• Variety: Sets may include multiple French curves to cover a wide range of curve profiles.
• Thickness: Thin enough to place precisely on the drawing without obscuring details.

Uses in architectural drawings

• Drawing complex curves such as arches, cornices, and mouldings.
• Creating smooth transitions between straight lines and curved elements.
• Detailing ornamental features and landscaping contours.
• Refining freehand sketches into precise technical curves.
• Assisting in the representation of organic shapes in architectural plans.

Handling and maintenance

• Clean frequently to avoid smudging lines on drawings.
• Store flat or in designated holders to prevent warping.
• Avoid scratches that can affect curve accuracy.
• Use gently to prevent cracking or breaking of thin edges.
• Keep away from direct sunlight to prevent plastic warping or discoloration.

Chapter Summary

This chapter covered essential technical drawing tools and equipment such as the drawing board, set square, compasses, T square, and French curve, highlighting their specific functions in architectural drafting. It then explored the various technical drawing materials including pencils with different hardness grades, suitable drawing papers, erasers, and masking tape necessary for precise and clean drawings. The focus shifted to technical drawing techniques, emphasizing the importance of mastering plane geometry for accurate two-dimensional representations and solid geometry for three-dimensional forms. Understanding these fundamentals equips students with the skills to produce clear and professional architectural drawings. The chapter also addressed the recommended quantity and ratio of drawing tools to trainees to ensure effective practice and learning. Overall, the content provided a comprehensive foundation for applying architectural drawing techniques in practical settings.