ISO 965-3-2021 PDF

Full title and description

ISO 965-3:2021 — ISO general purpose metric screw threads — Tolerances — Part 3: Limit deviations for screw threads. This part specifies the limit deviations for pitch and crest diameters of ISO general-purpose metric screw threads (M) that conform to ISO 261 and use the basic profile in accordance with ISO 68-1.

Abstract

ISO 965-3:2021 defines the numerical limit deviations for the pitch and crest (minor/major-related) diameters for ISO general-purpose metric screw threads. The deviations given are derived from the fundamental deviations and tolerances set out in ISO 965-1 and are intended to be used with the recommended tolerance classes for general-purpose metric threads.

General information

• Status: Published (current).
• Publication date: 6 July 2021.
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 21.040.10 — Metric screw threads.
• Edition / version: Edition 4 (2021).
• Number of pages: 26 pages.

Primary bibliographic and lifecycle details are published on the ISO catalogue entry for ISO 965-3:2021.

Scope

This part of ISO 965 specifies limit deviations for pitch and crest diameters for ISO general purpose metric screw threads (M) conforming to ISO 261 with the basic profile given in ISO 68‑1. The values in this part are derived from the fundamental deviations and tolerances in ISO 965‑1 and are intended for use with the recommended tolerance classes for general-purpose metric threads. The document replaces the earlier ISO 965‑3 editions (1998 and its corrigendum).

Key topics and requirements

• Definition of limit deviations for pitch diameters and crest diameters for ISO metric general-purpose threads.
• Derivation of limit deviations from the fundamental deviations and tolerances given in ISO 965-1.
• Application to recommended tolerance classes for general-purpose metric screw threads (for design, manufacture and inspection).
• Normative references to related thread vocabulary and profile standards (e.g., ISO 5408, ISO 68‑1, ISO 261).
• Tables and numerical limits for the specified thread sizes and tolerance positions (presented in tabular form in the standard).

These requirements provide the dimensional limits needed by designers, manufacturers and quality personnel to ensure interchangeability of metric threaded parts.

Typical use and users

Used by mechanical designers, fastener manufacturers, machining and tooling engineers, metrology and quality-control personnel, procurement teams specifying threaded parts, and standards organizations. Typical applications include specifying allowable thread size deviations in drawings, producing inspection plans for threaded components, and ensuring interchangeability of bolts, nuts and threaded machine parts.

Related standards

ISO 965-3:2021 is part of the ISO 965 series and is closely linked to: ISO 965-1 (Principles and basic data), ISO 965-2 (Limits of sizes for internal and external threads), ISO 68-1 (Basic profile for metric screw threads), ISO 261 (Standard metric screw thread — general plan), ISO 5408 (Screw threads — Vocabulary), ISO 724 (Basic dimensions for metric screw threads). These references are cited or used normatively within the part.

Keywords

metric screw threads, thread tolerances, limit deviations, pitch diameter, crest diameter, ISO 965, interchangeability, tolerance classes, ISO/TC 1

FAQ

Q: What is this standard?

A: ISO 965-3:2021 is an international standard that specifies limit deviations for the pitch and crest diameters of ISO general-purpose metric screw threads (M).

Q: What does it cover?

A: It covers numerical limit deviations (tables and rules) for the pitch and crest diameters derived from ISO 965‑1, for use with the recommended tolerance classes of ISO general-purpose metric threads that conform to ISO 261 and ISO 68‑1.

Q: Who typically uses it?

A: Mechanical designers, fastener and component manufacturers, inspection and quality engineers, procurement/specifiers, and standards bodies use it to ensure threaded part interchangeability and to define inspection limits.

Q: Is it current or superseded?

A: It is current (published 6 July 2021) and supersedes the previous ISO 965‑3:1998 edition (and its corrigendum).

Q: Is it part of a series?

A: Yes — ISO 965-3 is Part 3 of the ISO 965 series on general purpose metric screw threads — tolerances. Other parts include ISO 965‑1 and ISO 965‑2 (and related parts covering special conditions such as galvanizing).

Q: What are the key keywords?

A: Metric screw threads; tolerances; limit deviations; pitch diameter; crest diameter; interchangeability; tolerance classes; ISO 965.