ISO/PRF 4026

Fasteners - Hexagon socket set screws with flat point

ISO 4026:2003 specifies the characteristics of hexagon socket set screws with flat point and threads from M1,6 up to and including M24 and of product grade A.

Fixations — Vis sans tête à six pans creux, à bout plat

L'ISO 4026:2003 spécifie les caractéristiques des vis sans tête à six pans creux, à bout plat, de filetage M1,6 à M24 inclus et de grade A.

General Information

• Status: Not Published
• ICS: 21.060.10 - Bolts, screws, studs
• Technical Committee: ISO/TC 2/SC 11 - Fasteners with metric external thread
• Drafting Committee: ISO/TC 2/SC 11 - Fasteners with metric external thread
• Current Stage: 5020 - FDIS ballot initiated: 2 months. Proof sent to secretariat
• Start Date: 23-Dec-2025
• Completion Date: 27-Dec-2025

Relations

• Revises: ISO 4026:2003 - Hexagon socket set screws with flat point
• Effective Date: 04-Nov-2023

Overview

ISO/PRF 4026 (ISO 4026) defines the characteristics of hexagon socket set screws with flat point (product grade A). The 2026 draft covers metric coarse‑pitch threads from M1.6 to M30 for steel and M1.6 to M24 for stainless steel. The standard specifies geometry, dimensional tables, tolerances, surface condition options and labelling/marking provisions for these non‑tensile fasteners.

Key topics and requirements

• Scope and usage: Applies to hexagon socket set screws with flat point; set screws are not intended for tensile loading.
• Dimensions and forms: Detailed figures and tables give socket form, point geometry, standard lengths and dimensional limits (see Tables 1–2). Broached sockets and permissible socket mouth features are included.
• Threading and tolerances: Thread requirements reference ISO 724 and ISO 965‑1. Typical tolerance class and product grade references (e.g., product grade A and tolerance guidance from ISO 4759‑1) are identified.
• Materials and mechanical properties: Steel and stainless‑steel options are covered. Hardness classes and stainless grades are referenced to ISO 898‑5 (steel set screws) and ISO 3506‑3 (stainless set screws).
• Surface condition and coatings: As‑processed, clean and bright, and passivated conditions are referenced; electroplated and zinc‑flake coatings are included by reference to ISO 4042 and ISO 10683.
• Inspection and acceptance: Acceptance inspection and limits for surface discontinuities refer to ISO 3269 and ISO 6157‑1. Gauging of hexagon sockets follows ISO 23429.
• Marking and labelling: Product marking is optional unless agreed. Package labelling must include the ISO reference, thread size and nominal length, material/hardness/grade info, surface condition, manufacturer ID, lot number and quantity.

Applications and users

• Practical uses: securing collars, pulleys, set collars, gears and components to shafts or within assemblies where holding by friction or bearing on a shaft is required (not for primary tensile loads).
• Primary users: fastener manufacturers, suppliers and distributors; mechanical designers, procurement and quality/inspection engineers who specify and accept fasteners; maintenance and assembly teams needing clear identification of fastener grade and finish.

Related standards

Key referenced standards include:

• ISO 724, ISO 965‑1 (threads and tolerances)
• ISO 898‑5 (mechanical properties for steel set screws)
• ISO 3506‑3 (stainless‑steel set screws)
• ISO 4042, ISO 10683 (coatings)
• ISO 4759‑1 (product grade tolerances)
• ISO 23429 (socket gauging)

Keywords: ISO 4026, hexagon socket set screws with flat point, set screws, fasteners standard, M1.6–M30, product grade A, hex socket, flat point.

Standards Content (Sample)

International
Standard
ISO 4026
Fourth edition
Fasteners — Hexagon socket set
screws with flat point
Fixations — Vis sans tête à six pans creux, à bout plat
PROOF/ÉPREUVE
Reference number
ISO 4026:2026(en) © ISO 2026
ISO 4026:2026(en)
© ISO 2026
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
PROOF/ÉPREUVE
ii
ISO 4026:2026(en)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Dimensions . 2
5 Requirements and reference International Standards . 4
6 Marking and labelling . 5
6.1 Marking on product . .5
6.2 Labelling on package .5
7 Designation . 5
Bibliography . 6
PROOF/ÉPREUVE
iii
ISO 4026:2026(en)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 2, Fasteners, Subcommittee SC 11, Fasteners
with metric external thread, in collaboration with the European Committee for Standardization (CEN)
Technical Committee CEN/TC 185, Fasteners, in accordance with the Agreement on technical cooperation
between ISO and CEN (Vienna Agreement).
This fourth edition cancels and replaces the third edition (ISO 4026:2003), which has been technically
revised.
The main changes are as follows:
— M30 has been added for steel hexagon socket set screws;
— for d ≤ 1,00, the tolerance of d has been modified to h13 according to ISO 4753:2011, Table 1,
p,max p
Footnote b;
— approximate masses have been deleted in Table 2;
— non-ferrous metal screws have been deleted (as a consequence of the withdrawal of ISO 8839);
— for stainless steel fasteners, “Plain” has been changed to “Clean and bright”, and “Passivated” has been
added in Table 3;
— specifications for marking and labelling have been added as Clause 6.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
PROOF/ÉPREUVE
iv
International Standard ISO 4026:2026(en)
Fasteners — Hexagon socket set screws with flat point
1 Scope
This document specifies the characteristics of hexagon socket set screws with flat point, with metric coarse
pitch threads M1,6 to M30 for steel and M1,6 to M24 for stainless steel, and with product grade A.
Set screws are not intended for use under tensile load.
If, in certain cases other specifications are requested, hardness classes and stainless steel grades can be
selected from ISO 898-5 or ISO 3506-3, and dimensional options from ISO 888, ISO 965-1 or ISO 4753.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 225, Fasteners — Bolts, screws, studs and nuts — Symbols and descriptions of dimensions
ISO 724, ISO general purpose metric screw threads — Basic dimensions
ISO 888, Fasteners — Bolts, screws and studs — Nominal lengths and thread lengths
ISO 898-5, Mechanical properties of fasteners made of carbon steel and alloy steel — Part 5: Set screws and
similar threaded fasteners with specified hardness classes — Coarse thread and fine pitch thread
ISO 965-1, ISO general purpose metric screw threads — Tolerances — Part 1: Principles and basic data
ISO 1891-4, Fasteners — Vocabulary — Part 4: Control, inspection, delivery, acceptance and quality
ISO 3269, Fasteners — Acceptance inspection
ISO 3506-3, Fasteners — Mechanical properties of corrosion resistant stainless steel fasteners — Part 3: Set
screws (and similar fasteners not under tens
...

ISO/TC 2/SC 11
Secretariat: DIN
Date: 2025-12-062026-xx
Fasteners — Hexagon socket set screws with flat point
Fixations — Vis sans tête à six pans creux, à bout plat
PROOF
This draft is submitted to a parallel vote in ISO, CEN.
This draft is submitted to a parallel vote in ISO, CEN.
Voting begVoting beginins s on:on: 20202626--0101--0101
Voting termiVoting terminatesnates on: on:

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication
may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying,
or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO
at the address below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: + 41 22 749 01 11
EmailE-mail: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
Contents
Foreword . iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Dimensions. 2
5 Requirements and reference International Standards . 4
6 Marking and labelling . 5
6.1 Marking on product . 5
6.2 Labelling on package . 5
7 Designation . 5
Bibliography . 7

iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types of
ISO documents should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights
in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s)
which may be required to implement this document. However, implementers are cautioned that this may not
represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 2, Fasteners, Subcommittee SC 11, Fasteners
with metric external thread, in collaboration with the European Committee for Standardization (CEN)
Technical Committee CEN/TC 185, Fasteners, in accordance with the Agreement on technical cooperation
between ISO and CEN (Vienna Agreement).
This thirdfourth edition cancels and replaces the secondthird edition (ISO 4026:2003), which has been
technically revised.
The main changes are as follows:
— — M30 has been added for steel hexagon socket set screws;
— — for d ≤ 1,00, the tolerance of d has been modified to h13 according to ISO 4753:2011, Table 1,
p,max p
Footnote b;
— — approximate masses have been deleted in Table 2;
— — non-ferrous metal screws have been deleted (as a consequence of the withdrawal of ISO 8839);
— — for stainless steel fasteners, “Plain” has been changed to “Clean and bright”, and “Passivated” has been
added in Table 3;
— — specifications for marking and labelling have been added as Clause 6.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
Fasteners — Hexagon socket set screws with flat point
1 Scope
This document specifies the characteristics of hexagon socket set screws with flat point, with metric coarse
pitch threads M1,6 to M30 for steel and M1,6 to M24 for stainless steel, and with product grade A.
Set screws are not intended for use under tensile load.
If, in certain cases other specifications are requested, hardness classes and stainless steel grades can be
selected from ISO 898--5 or ISO 3506--3, and dimensional options from ISO 888, ISO 965-1 or ISO 4753.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 225, Fasteners — Bolts, screws, studs and nuts — Symbols and descriptions of dimensions
ISO 724, ISO general purpose metric screw threads — Basic dimensions
ISO 888, Fasteners — Bolts, screws and studs — Nominal lengths and thread lengths
ISO 898--5, Mechanical properties of fasteners made of carbon steel and alloy steel — Part 5: Set screws and
similar threaded fasteners with specified hardness classes — Coarse thread and fine pitch thread
ISO 965--1, ISO general purpose metric screw threads — Tolerances — Part 1: Principles and basic data
ISO 1891--4, Fasteners — Vocabulary — Part 4: Control, inspection, delivery, acceptance and quality
ISO 3269, Fasteners — Acceptance inspection
ISO 3506--3, Fasteners — Mechanical properties of corrosion resistant stainless steel fasteners — Part 3: Set
screws (and similar fasteners not under tensile stress) with specified grades and hardness classes
ISO 4042, Fasteners — Electroplated coating systems
ISO 4753, Fasteners — Ends of parts with external ISO metric thread
ISO 4759--1, Tolerances for fasteners — Part 1: Bolts, screws, studs and nuts — Product grades A, B and C
ISO 6157--1, Fasteners — Surf
...