ISO/PRF 4028

ISO/TC 2/SC 11
Secretariat: DIN
Date: 2025-12-082026-xx
Fasteners — Hexagon socket set screws with dog point
Fixations — Vis sans tête à six pans creux, à téton
PROOF
This draft is submitted to a parallel vote in ISO, CEN.
This draft is submitted to a parallel vote in ISO, CEN.
Voting begins on: 2026-01-01
Voting begins on: 2026-01-01
Voting terminates on:
Voting terminates on:
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Published in Switzerland
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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 . 6
Annex A (informative) Cut-off slugs at machined set screws with dog point . 7
Bibliography . 8

iii
Foreword
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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 4028:2003), 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;
+IT13
— — for z ≤ 1,00, the tolerance of z has been modified to  according to ISO 4753:2011, Table 1,
min
Footnote d;
— — approximate masses have been deleted in Table 2ength table;;
— — 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;
— Annex A— Annex A has been added for cut-off slugs at machined set screws with dog point.
iv
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.
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Fasteners — Hexagon socket set screws with dog point
1 Scope
This document specifies the characteristics of hexagon socket set screws with dog 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 — Surface discontinuities — Part 1: Bolts, screws and studs for general requirements
ISO 8991, Designation system for fasteners
ISO 8992, Fasteners — General requirements for bolts, screws, studs and nuts
ISO 10683, Fasteners — Non-electrolytically applied zinc flake coating systems
ISO 23429, Gauging of hexagon sockets
...