Overview
ISO 6410-1:1993 - Technical drawings - Screw threads and threaded parts - Part 1: General conventions specifies standardized methods for representing screw threads and threaded parts on technical drawings. It defines both detailed and conventional graphical representations, rules for showing threads in views and sections, how to indicate assembled threaded parts, and the conventions for designation and dimensioning (including direction of lead). The part complements ISO 6410 series (Parts 2 and 3) and links to general drawing standards such as ISO 128 and ISO 129.
Key topics and requirements
- Representation methods
- Detailed vs. conventional (simplified) representation of threads in side views, sections and end views.
- Prefer representing helices as straight lines in side views when possible.
- Line types and spacing
- Crests of visible threads by a continuous thick line; roots by continuous thin line.
- Minimum spacing between crest and root lines: not less than twice the thickness of the thick line or 0.7 mm, whichever is larger. (Notes give CAD guidance: e.g., 1.5 mm often acceptable for d > 8 mm.)
- End and hidden views
- End views: thread roots shown as a portion of a circle (approx. 3/4 circumference) in thin line.
- Hidden threads: crests and roots shown with dashed thin lines.
- Hatching and sections
- Hatching of sectioned threaded parts extends to crest-defining line; inclined thin continuous lines may be used where functionally necessary.
- Limits, run-outs and assemblies
- Show the limit of length of full-depth thread (visible by continuous thick line; hidden by dashed line).
- Thread run-outs may be omitted where possible.
- In assemblies, external threads are shown covering internal threads and are not hidden.
- Designation and dimensioning
- Thread designation includes type (symbol), nominal diameter, lead/pitch, direction of lead, tolerance class, engagement (S/L/N) and number of starts.
- Nominal diameter refers to the crest for external threads and to the root for internal threads.
- Thread length normally refers to full-depth length; blind hole depth may be omitted or shown as 1.25 × thread length when unspecified.
- Left‑hand threads must be marked (LH); RH may be marked if necessary.
Applications and users
- Practical for: mechanical engineers, design drafters, CAD technicians, manufacturing engineers, shop floor personnel, quality inspectors and technical documentation authors.
- Use cases: preparing manufacturing drawings, assembly documentation, procurement specifications for fasteners, CAD drawing standards, and inspection/QA procedures involving threaded parts and fasteners.
Related standards
- ISO 6410-2 (Screw thread inserts), ISO 6410-3 (Simplified representation)
- ISO 128 (Technical drawings - general presentation), ISO 129 (Dimensioning), ISO 225 (Fastener symbols/dimensions), ISO 4753 (Ends of parts), ISO 261/262/965 (metric thread series and tolerances)
Keywords: ISO 6410-1, screw threads, threaded parts, technical drawings, thread representation, thread designation, dimensioning, lead direction, CAD drafting, fastener documentation.
Open preview (PDF)Technical drawings — Screw threads and threaded parts — Part 1: General conventions