ISO 3353-1:2020
(Main)Aerospace - Lead and runout threads - Part 1: Rolled external threads
Aerospace - Lead and runout threads - Part 1: Rolled external threads
This document specifies the lead and runout requirements for rolled external threads for aerospace construction, and the inspection method to be used in case of dispute. It is applicable whenever it is referenced in a definition document.
Aéronautique et espace — Filets incomplets, débuts et fins de filets — Partie 1: Filetages extérieurs roulés
General Information
Relations
Overview
ISO 3353-1:2020 - "Aerospace - Lead and runout threads - Part 1: Rolled external threads" defines the form, limits and inspection method for incompletely formed rolled external threads used in aerospace construction. The document specifies what constitutes lead threads, runout threads and completely formed threads, sets root-radius and profile requirements, and prescribes an optical inspection procedure to be used in case of dispute. It is applicable whenever a definition document references it.
Key topics and technical requirements
- Scope and definitions
- Clear definitions of lead thread, runout thread and completely formed thread to standardize interpretation across manufacturers and inspectors.
- Geometric requirements
- Incomplete-thread flanks at the root shall be joined by a radius (or two radii and a flat) that is smooth and free of abrupt tool marks.
- The root radius of incompletely formed threads must be greater than or equal to the minimum root radius specified in the applicable definition document.
- Lead thread limits
- The lead-thread region must lie within the limits defined in the applicable thread definition document; profile-projection comparator charts (Figure 10) are provided for inspection.
- Runout thread configurations
- Runout requirements cover several shank types: normal shank, pitch-diameter shank, stepped shank, screws threaded to the head / bolts to a shoulder, and oversized bolts. Each configuration has corresponding inspection charts (Figures 11–14).
- Inspection method
- Manufacturers may use any method that demonstrates conformity, but optical projection is mandated in disputes.
- Charts are intended for use with a profile projection comparator having magnification ≥ ×20.
- Practical inspection steps include locating the first/last completely formed thread, then aligning the specified flank to the chart reference lines.
- Practical note (Annex A)
- Assembling the bolt with a GO screw ring gauge (without entering the chamfer) is the preferred, faster method for checking lead and runout threads; profile projection is more accurate but operator-dependent and slower.
Applications and users
- Intended for aerospace fastener manufacturers, designers of threaded components, quality/inspection engineers, maintenance and repair organizations, and procurement/specification writers.
- Used to ensure consistent rolled external thread starts and finishes on bolts and screws in aircraft and space hardware, to support interchangeability, fatigue performance and assembly reliability.
- Also referenced in definition documents and repair/overhaul procedures where threaded terminations are critical.
Related standards
- Part of the ISO 3353 series addressing incomplete threads for aerospace; users should consult the relevant thread definition documents and other parts of the ISO 3353 series as referenced.
- Prepared by ISO/TC 20 (Aircraft and space vehicles), SC 4 (Aerospace fastener systems).
Keywords: ISO 3353-1, lead threads, runout threads, rolled external threads, aerospace fasteners, thread inspection, profile projection comparator, GO screw ring gauge.
Frequently Asked Questions
ISO 3353-1:2020 is a standard published by the International Organization for Standardization (ISO). Its full title is "Aerospace - Lead and runout threads - Part 1: Rolled external threads". This standard covers: This document specifies the lead and runout requirements for rolled external threads for aerospace construction, and the inspection method to be used in case of dispute. It is applicable whenever it is referenced in a definition document.
This document specifies the lead and runout requirements for rolled external threads for aerospace construction, and the inspection method to be used in case of dispute. It is applicable whenever it is referenced in a definition document.
ISO 3353-1:2020 is classified under the following ICS (International Classification for Standards) categories: 49.030.10 - Screw threads. The ICS classification helps identify the subject area and facilitates finding related standards.
ISO 3353-1:2020 has the following relationships with other standards: It is inter standard links to ISO 3353-1:2002. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
You can purchase ISO 3353-1:2020 directly from iTeh Standards. The document is available in PDF format and is delivered instantly after payment. Add the standard to your cart and complete the secure checkout process. iTeh Standards is an authorized distributor of ISO standards.
Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 3353-1
Second edition
2020-12
Aerospace — Lead and runout
threads —
Part 1:
Rolled external threads
Aéronautique et espace — Filets incomplets, débuts et fins de filets —
Partie 1: Filetages extérieurs roulés
Reference number
©
ISO 2020
© ISO 2020
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
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols for threads . 2
5 Requirements . 2
5.1 General requirements . 2
5.2 Lead threads . 2
5.3 Runout threads . 3
5.3.1 Normal shank . 3
5.3.2 Pitch diameter shank . 4
5.3.3 Stepped shank . 4
5.3.4 Screws threaded to the head and bolts threaded to a shoulder . 5
5.3.5 Oversized bolts . 6
6 Inspection method . 7
6.1 General . 7
6.2 Use of the charts . 7
6.3 Procedure . 7
6.3.1 For lead threads . 7
6.3.2 For runout threads . 7
Annex A (informative) Comments on inspection method .10
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).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
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 20, Aircraft and space vehicles
Subcommittee SC 4, Aerospace fastener systems.
This second edition cancels and replaces the first edition (ISO 3353-1:2002), of which it constitutes a
minor revision.
The main changes compared to the previous edition are as follows:
— update of the term “lead threads”;
— editorially revised.
A list of all parts in the ISO 3353 series can be found on the ISO website.
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 © ISO 2020 – All rights reserved
INTERNATIONAL STANDARD ISO 3353-1:2020(E)
Aerospace — Lead and runou
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.
Loading comments...