ISO 4161-2012 PDF

Full title and description

ISO 4161:2012 — Hexagon nuts with flange, style 2 — Coarse thread. This International Standard specifies the dimensional and product‑grade characteristics for hexagon nuts with a flange (style 2) supplied with metric coarse threads, intended for general engineering fastening applications.

Abstract

ISO 4161:2012 defines the geometry, thread range and product grades for hexagon flange nuts (style 2) with metric coarse threads from M5 to M20 inclusive. It gives dimensions and requirements for product grade A for threads up to and including M16 and product grade B for threads above M16. The standard replaces the previous 1999 edition.

General information

• Status: Published / valid International Standard.
• Publication date: 2012 (Edition 3, published September 2012; approved August 2012 in committee records).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 21.060.20 (Nuts / fasteners).
• Edition / version: Edition 3 — ISO 4161:2012.
• Number of pages: Published as a short International Standard (official ISO listing: 7 pages).

Scope

ISO 4161:2012 applies to hexagon nuts with a flange (style 2) having metric coarse threads in the nominal size range M5 to M20 inclusive. The standard specifies dimensional characteristics and product grades (A and B) for these nuts and is intended to be used where standardized flange nut dimensions and grades are required in assembly, manufacturing and procurement. It supersedes ISO 4161:1999.

Key topics and requirements

• Dimensional specifications and nominal sizes for flange (style 2) hexagon nuts covering M5 to M20 coarse threads.
• Product grades: Grade A for threads up to and including M16; Grade B for threads above M16.
• Defined values for across‑flats, flange diameter and nut height appropriate to style 2 flange nuts.
• Reference to related tolerancing and thread standards (used in design/inspection), and interoperability with other ISO fastener standards.
• Replacement of the 1999 edition and consolidation of dimensional/product‑grade rules for flange hex nuts.

Typical use and users

Typical users include fastener manufacturers, component designers, mechanical engineers, procurement and quality/inspection teams who specify or verify hexagon flange nuts for machinery, automotive, electrical enclosures and general mechanical assemblies. The standard is used to ensure interchangeability, correct fit with bolts and compliance with product‑grade requirements.

Related standards

ISO 4161 is part of the family of ISO fastener standards. Commonly referenced or complementary standards include ISO 4032 / ISO 4033 / ISO 4034 series (other hexagon nut styles and heights), ISO 7042 / ISO 7043 (prevailing torque/locking nuts and flange locking types), ISO 4759‑1 (tolerances for fasteners — product grades), and general thread standards such as ISO 965 / ISO 261 where applicable. National and regional equivalents (for example EN/DIN flange nut standards) may also be used alongside ISO 4161.

Keywords

hexagon nut, flange nut, style 2, coarse thread, metric thread, M5–M20, product grade A, product grade B, fasteners, ISO 4161, nut dimensions

FAQ

Q: What is this standard?

A: ISO 4161:2012 is the International Standard that specifies dimensional and product‑grade requirements for hexagon nuts with flange, style 2, with metric coarse threads.

Q: What does it cover?

A: It covers nuts with flange (style 2) in nominal sizes M5 to M20 inclusive, setting flange and hexagon dimensions and assigning product grades (A for ≤ M16, B for > M16). It does not replace thread form standards or mechanical property standards; those are referenced where required.

Q: Who typically uses it?

A: Manufacturers of nuts, design and mechanical engineers, procurement/specification professionals and quality inspectors use ISO 4161 to ensure dimensional interchangeability and correct selection of product grade for applications.

Q: Is it current or superseded?

A: ISO 4161:2012 is the current published edition and it replaced ISO 4161:1999. Users should confirm national adoptions or later revisions if required for specific procurement or regulatory contexts.

Q: Is it part of a series?

A: Yes — ISO 4161 sits within the broader family of ISO fastener standards covering hexagon nuts, bolts and related products (for example ISO 4032/4033/4034, ISO 7042/7043, ISO 4759‑1). Designers commonly use these standards together when specifying threaded assemblies.

Q: What are the key keywords?

A: Key keywords are: hexagon nut, flange nut, style 2, coarse thread, M5–M20, product grade A, product grade B, fasteners, dimensions, ISO 4161.