ISO 5845-1:1995

Overview

ISO 5845-1:1995 establishes the general principles for the simplified representation of holes, bolts (screws), rivets and similar fasteners on technical drawings. It is intended to provide a universal, reproducible method of showing fastener locations and types so that drawings remain clear under microcopying and reproduction. Part 1 focuses on structural metalwork and general drafting practice; a companion Part 2 addresses rivets for aerospace equipment.

Key Topics

• Symbolic representation: Fasteners are shown by standard symbols when viewed on planes normal or parallel to their axes. Symbols must be drawn with the line types and weights specified (in accordance with ISO 128) to ensure legibility.
• Projection conventions: On projection planes normal to fastener axes, the position is indicated by a cross; an optional central dot (diameter = five times line thickness) may be used to ease template copying.
• Line types: Symbol elements use continuous thick lines (type A) and, for views parallel to the axis, a horizontal thin line (type B) combined with thick elements, following ISO 128 conventions.
• Countersinking and variants: The standard differentiates holes and fasteners with and without countersinking, and provides distinct symbolic forms for workshop-fitted, site-fitted or site-drilled configurations.
• Dimensioning and labelling: Diameter, fastener designation and group counts are indicated with leader lines and dimensioning rules that conform to ISO 129. Designations reference the relevant fastener standard (for example, M12 x 50 for a metric bolt or Ø13 for a hole).
• Reproducibility: Symbols and annotations are chosen to preserve clarity after reproduction and microcopying, making them suitable for manufacturing templates and inspection documents.

Applications

• Preparing consistent engineering drawings for structural metalwork and assemblies.
• Creating production and inspection templates that remain accurate after copying.
• Defining clear fastener specifications for procurement, installation and maintenance.
• Integrating symbolic conventions into CAD drafting standards and drawing templates to ensure cross-disciplinary communication.

Related Standards

• ISO 128 - Technical drawings: general principles of presentation (line types and weights).
• ISO 129 - Technical drawings: dimensioning rules and indications.
• ISO 10209 (Parts 1 & 2) - Vocabulary for technical product documentation.
• ISO 5845-2:1995 - Part 2: Rivets for aerospace equipment.

By following ISO 5845-1:1995, engineers and drafters ensure fastener information is communicated clearly and consistently across design, manufacture and field installation, reducing errors and improving production efficiency.