ISO 2857-1973 amd2-1986 PDF

Full title and description

ISO 2857:1973/Amd 2:1986 — Ground thread taps for ISO metric threads of tolerances 4H to 8H and 4G to 6G, coarse and fine pitches — Manufacturing tolerances on the threaded portion (Amendment 2). This one‑page amendment updates or clarifies manufacturing tolerances that apply to the threaded portion of ground taps covered by ISO 2857:1973.

Abstract

This amendment (Amendment 2, published September 1986) applies to ISO 2857:1973 and provides specific corrections/additions to the tolerances and execution requirements for the threaded portion of ground thread taps intended for ISO metric internal threads (designation ranges 4H–8H and 4G–6G) in both coarse and fine pitches. The amendment is published as a single‑page document.

General information

• Status: Published (International Standard — amendment).
• Publication date: September 1986 (Edition 1, published 1986‑09; common listing 25 September 1986).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 25.100.50 (Taps and threading dies).
• Edition / version: Edition 1 (Amendment 2 to ISO 2857:1973).
• Number of pages: 1 (amendment published as a single page).

Scope

This amendment modifies the manufacturing‑tolerance provisions of ISO 2857:1973 that govern ground thread taps used to produce internal ISO metric threads having tolerance grades 4H to 8H and 4G to 6G, for both coarse and fine thread pitches. It is limited to the tolerances and execution of the threaded (cutting) portion of ground taps and is intended to be read in conjunction with the base standard ISO 2857:1973.

Key topics and requirements

• Manufacturing tolerances for the threaded portion of ground thread taps (clarifications or corrections to the base standard).
• Application to ISO metric internal thread tolerance classes 4H–8H and 4G–6G.
• Coverage for both coarse and fine thread pitches; intended for short taps specified in ISO 529 and other ground taps of the same diameters and pitches.
• Issued as a concise technical amendment (single‑page), so users must apply it to the original ISO 2857:1973 text when implementing tolerances.

Typical use and users

Manufacturers of taps and threading tools, tooling engineers, quality and metrology personnel in machining and fastener industries, standards committees and purchasers of tapping tools refer to this amendment to ensure the correct manufacturing tolerances are applied to ground thread taps intended to produce ISO metric internal threads in the specified tolerance ranges. The amendment is used together with ISO 2857:1973 (and related normative documents).

Related standards

Primary related document: ISO 2857:1973 (base standard). Other related publications include ISO 529 (short taps), ISO 965 series (general thread tolerances and designations) and the earlier Amendment 1 to ISO 2857 (1984) as well as any corrigenda associated with ISO 2857. Users should consult the base standard and its published amendments/corrigenda together.

Keywords

ground thread taps, ISO metric threads, manufacturing tolerances, 4H, 5H, 6H, 7H, 8H, 4G, 5G, 6G, coarse pitch, fine pitch, tapping tools, ISO 2857, amendment 1986.

FAQ

Q: What is this standard?

A: ISO 2857:1973/Amd 2:1986 is Amendment 2 (published September 1986) to ISO 2857:1973. It is a one‑page amendment that updates or clarifies the manufacturing tolerances for the threaded portion of ground thread taps intended for certain ISO metric internal thread tolerance classes.

Q: What does it cover?

A: It covers manufacturing tolerances and execution requirements for the threaded (cutting) portion of ground taps used to produce ISO metric internal threads of tolerances 4H to 8H and 4G to 6G, for both coarse and fine pitches; it must be applied alongside the base ISO 2857:1973 text.

Q: Who typically uses it?

A: Tool manufacturers, machining and quality engineers, standards committees and procurement/specification writers for tooling and fasteners use this amendment to ensure tapped-hole and tap‑manufacture tolerances meet international requirements.

Q: Is it current or superseded?

A: The amendment itself was published in 1986 and remains the published Amendment 2 to ISO 2857:1973; users should check the current status of ISO 2857 (and any later revisions or consolidations) with ISO or their national standards body to confirm whether a newer consolidated edition has replaced the original plus amendments. The ISO catalogue lists ISO 2857:1973 and its amendments (including Amd 2:1986) as published documents.

Q: Is it part of a series?

A: Yes — it is an amendment to the ISO 2857 series (the base standard ISO 2857:1973). It is related to other ISO documents covering taps and thread tolerances such as ISO 529 (short taps) and the ISO 965 series (general internal thread tolerances).

Q: What are the key keywords?

A: Ground thread taps; ISO metric threads; manufacturing tolerances; 4H–8H; 4G–6G; coarse pitch; fine pitch; taps and threading dies; ISO 2857; amendment 1986.