ISO 7091-2000 PDF

Full title and description

ISO 7091:2000 — Plain washers — Normal series — Product grade C. This International Standard specifies the characteristics, preferred dimensions and technical delivery conditions for normal‑series flat (plain) washers of product grade C manufactured in hardness class 100 HV, for nominal thread diameters from 1.6 mm up to and including 64 mm.

Abstract

ISO 7091:2000 defines a normal series of plain washers (product grade C) intended for general fastening use where a 100 HV hardness washer is appropriate. It gives preferred nominal diameters, hole diameters, outer diameters, thicknesses and basic technical requirements and notes typical combinations with bolts, screws and nuts (referencing other fastener standards for complementary dimensions and selection guidance).

General information

• Status: Published — current edition confirmed (confirmed 22 June 2021).
• Publication date: June 2000 (Edition 2, 2000).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 21.060.30 (Washers, locking elements / Fasteners).
• Edition / version: Edition 2 (2000).
• Number of pages: 4.

Scope

This standard applies to plain (flat) washers of the normal series in product grade C with hardness class 100 HV, for nominal thread diameters (nominal sizes) from 1.6 mm to 64 mm inclusive. It provides preferred dimensional combinations, tolerance guidance and notes on suitable applications (for example, the washer grade C 100 HV is recommended for use with hexagon bolts of product grade C up to property class 6.8 and hexagon nuts of product grade C up to property class 6). When different dimensions are required, ISO 887 (plain‑washer general plan) is the reference for selecting alternate sizes.

Key topics and requirements

• Defined dimensional data for normal‑series plain washers: nominal thread size, hole (inner) diameter, outer diameter and thickness for preferred combinations between 1.6 mm and 64 mm.
• Material hardness class requirement: 100 HV for product grade C washers and associated notes on suitability with fastener property classes.
• Technical delivery conditions and marking recommendations for product grade C washers.
• Compatibility guidance — recommended combinations with bolts, screws and nuts and cross‑references to ISO 887 for other sizes.
• Reference to tolerance and inspection practices (tolerances normally handled by applicable tolerance standards for fasteners and washers).

Typical use and users

Used by fastener manufacturers, component suppliers, mechanical designers, procurement/specification engineers, quality and inspection personnel, and standards committees. Typical applications include machinery assembly, structural connections, general engineering fastening where standardized flat washers of product grade C are required.

Related standards

Standards commonly referenced or used alongside ISO 7091:2000 include ISO 887 (plain washers — general plan and full range of nominal dimensions), ISO 7089 (plain washers — normal series — product grade A), ISO 7094 (plain washers — extra large series — product grade C), ISO 4759‑3 (tolerances for washers — product grades A, C and F), ISO 4042 (electroplated coatings for fasteners), and ISO 272 (widths across flats for hexagon products). National and regional adoptions (EN ISO / DIN EN ISO) may republish the ISO text as a regional/national standard.

Keywords

plain washer, flat washer, normal series, product grade C, 100 HV, washer dimensions, fasteners, ISO 7091, nominal size, bolt/nut compatibility, tolerances

FAQ

Q: What is this standard?

A: ISO 7091:2000 is an International Standard that specifies the characteristics and preferred dimensions for normal‑series plain (flat) washers of product grade C in hardness class 100 HV, covering nominal thread diameters from 1.6 mm to 64 mm.

Q: What does it cover?

A: It covers dimensional data (inner/outer diameters and thicknesses for preferred combinations), hardness class requirement (100 HV), technical delivery considerations and guidance on suitable combinations with bolts, screws and nuts for general fastening use.

Q: Who typically uses it?

A: Fastener and washer manufacturers, mechanical and structural designers, procurement/specification engineers, quality inspectors and testing laboratories — anyone specifying or producing standardized flat washers for metric bolted assemblies.

Q: Is it current or superseded?

A: The current ISO edition is ISO 7091:2000 (Edition 2, published June 2000). The edition was reviewed and confirmed as the current ISO version in 2021. National/regional adoptions may carry different publication dates; the ISO edition itself remains the authoritative international text until replaced by a later ISO edition or amendment.

Q: Is it part of a series?

A: Yes — ISO 7091 is part of a set of ISO washer standards that cover different product grades and series (for example ISO 7089 for product grade A, ISO 7094 for extra large series product grade C) and should be used together with general washer/plating/tolerance standards such as ISO 887, ISO 4759‑3 and ISO 4042.

Q: What are the key keywords?

A: Plain washer, flat washer, normal series, product grade C, hardness 100 HV, nominal size 1.6–64 mm, fasteners, washer dimensions, ISO 7091.