Roymech engineering encyclopedia

Bolt and Rivet Hole Representation in Engineering Drawings (ISO Standards)




Solid Print 3D


Bolt and rivet holes in engineering drawings are represented using simplified symbols defined by ISO standards to improve clarity and reduce detail. These representations show hole size, type, and fastener position in plan and side views without drawing full geometry, making technical drawings easier to read and faster to produce.

Bolt and rivet holes are commonly represented in engineering drawings using simplified symbols to improve clarity and reduce drawing complexity. Standardised methods allow engineers to show hole types, assembly details, and fastener positions without excessive detail, ensuring consistency across designs.


Simplified Representation of Bolt and Rivet Holes


These notes follow the simplified drawing methods defined in the following standard:

BS EN ISO 5845-1 – Simplified representation of the assembly of parts with fasteners (Part 1: General principles).

This standard defines how bolt and rivet holes are represented in plan and side views to ensure clarity and consistency in engineering drawings.

Plan View Representation of Bolt and Rivet Holes

Side View Representation of Holes

The second figure shows the acceptable simplified representations of holes drilled for bolts or rivets-- Side view

Side View Representation with Fasteners

The third figure shows the acceptable simplified representations of holes with bolts or rivets-- Side view

Fastener Designation in Drawings

The fourth view simply shows how to conveniently indicate the bolt or rivet designation..

Why Simplified Hole Representation is Used

  • Reduces drawing complexity
  • Improves clarity in assemblies
  • Speeds up drafting and design
  • Follows international engineering standards
  • Focuses on function rather than detailed geometry

Types of Fastener Holes in Drawings

  • Bolt holes – Used for removable mechanical joints
  • Rivet holes – Used for permanent fastening
  • Clearance holes – Provide space for bolt insertion
  • Assembly holes – Used for alignment during assembly
  • Drilled and fitted holes – Used where precision fit is required

Key Drawing Conventions

  • Centre lines are used to indicate hole positions
  • Simplified symbols replace full geometric detail
  • Hidden lines are minimised unless necessary
  • Fastener sizes are indicated using standard notation (e.g. M12 bolt)
  • Section views may be used for clarity in complex assemblies

FAQs – Bolt and Rivet Hole Representation

How are bolt holes shown in engineering drawings?

Bolt holes are typically shown using simplified circles with centre lines in plan view and simplified profiles in side view, following ISO standards.

Why are holes drawn using simplified symbols?

Simplified symbols reduce drawing complexity and make technical drawings easier to interpret without unnecessary detail.

What standard covers bolt and rivet hole representation?

BS EN ISO 5845-1 defines the simplified representation of fasteners and holes in engineering drawings.

What is the difference between a bolt hole and a clearance hole?

A bolt hole matches the fastener size closely, while a clearance hole is slightly larger to allow easy assembly.

Do simplified drawings reduce accuracy?

No, they maintain all essential information while removing unnecessary detail, improving readability.



See Also