SIST ISO 9177-3:2023
(Main)Mechanical pencils for technical drawings - Part 3: Black leads - Bending strengths of HB leads
Mechanical pencils for technical drawings - Part 3: Black leads - Bending strengths of HB leads
This document specifies bending strengths and a test method for black leads of HB hardness degree used for mechanical pencils for technical drawings.
Porte-mines pour le dessin technique - Partie 3: Mines graphite — Résistance à la flexion des mines HB
Tehnični svinčniki za tehnično risanje - 3. del: Grafitni vložki - Upogibna trdnost grafitnih vložkov HB
Ta dokument določa upogibno trdnost in preskusno metodo za grafitne vložke trdote HB, ki se uporabljajo v tehničnih svinčnikih za tehnično risanje.
General Information
Relations
Overview
ISO 9177-3:2022 specifies bending strengths and a test method for black leads of HB hardness used in mechanical pencils for technical drawings. The standard defines minimum bending strength values by nominal lead diameter, a standardized three-point bending test procedure (including loading rates and anvil spacing), the formula for calculating bending strength, and the information required in the test report. It applies specifically to leads intended for technical drawing use (not general‑purpose leads).
Key Topics and Requirements
- Scope: Bending strength of HB black leads for mechanical pencils for technical drawings.
- Minimum bending strengths (σ, MPa) by nominal diameter:
- Polymer (P): 0.35 mm - 240 MPa; 0.5 mm - 190 MPa; 0.7 mm - 160 MPa; 1 mm - 95 MPa
- Ceramic (C): 2 mm - 70 MPa
- Note on diameters: 0.35 and 1 mm correspond to older designations 0.3 and 0.9 mm respectively.
- Test method (three‑point bend):
- Arrange lead on two supporting anvils and apply central load with a loading anvil.
- Loading rates (±10%): 0.1 N/s for 0.35, 0.5, 0.7, 1 mm leads; 0.5 N/s for 2 mm leads.
- Verify loading rates using a rigid test piece prior to testing.
- Anvil spacing (l): Polymer leads (0.35–1 mm) - 20 to 40 mm; Ceramic 2 mm - 40 to 60 mm.
- Calculate bending strength using σ = (8 F l) / (3 π d), where F is breaking load (N), l is span (mm), d is actual diameter (mm).
- Test report must include: reference to ISO 9177-3, lead type (P or C), actual diameter, test values F and l, calculated bending strength, test centre/name/date/signature.
Applications and Users
ISO 9177-3:2022 is relevant to:
- Mechanical pencil and lead manufacturers for product specification, quality control, and conformity with technical‑drawing performance expectations.
- Laboratories and test centres that perform lead strength testing and issue compliance reports.
- Procurement and specification writers in engineering, architecture, CAD/drafting tool supply chains who require durable HB leads for precise technical drawings.
- Regulatory/standards teams and product designers ensuring compatibility with ISO 9177 series requirements.
Using this standard helps ensure consistent lead durability, reliable performance in technical drawing applications, and clear, reproducible test results for product certification and quality assurance.
Related Standards
- ISO 9177-1: Classification, dimensions, performance requirements and testing (mechanical pencils for technical drawings)
- ISO 9177-2: Black leads - Classification and dimensions
- ISO 20318-1 and ISO 20318-2: Mechanical pencils and leads for general use (classification, dimensions, test methods)
Frequently Asked Questions
SIST ISO 9177-3:2023 is a standard published by the Slovenian Institute for Standardization (SIST). Its full title is "Mechanical pencils for technical drawings - Part 3: Black leads - Bending strengths of HB leads". This standard covers: This document specifies bending strengths and a test method for black leads of HB hardness degree used for mechanical pencils for technical drawings.
This document specifies bending strengths and a test method for black leads of HB hardness degree used for mechanical pencils for technical drawings.
SIST ISO 9177-3:2023 is classified under the following ICS (International Classification for Standards) categories: 01.100.40 - Drawing equipment; 97.180 - Miscellaneous domestic and commercial equipment. The ICS classification helps identify the subject area and facilitates finding related standards.
SIST ISO 9177-3:2023 has the following relationships with other standards: It is inter standard links to SIST ISO 9177-3:1995. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
You can purchase SIST ISO 9177-3:2023 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 SIST standards.
Standards Content (Sample)
SLOVENSKI STANDARD
01-september-2023
Nadomešča:
SIST ISO 9177-3:1995
Tehnični svinčniki za tehnično risanje - 3. del: Grafitni vložki - Upogibna trdnost
grafitnih vložkov HB
Mechanical pencils for technical drawings - Part 3: Black leads — Bending strengths of
HB leads
Porte-mines pour le dessin technique - Partie 3: Mines graphite — Résistance à la
flexion des mines HB
Ta slovenski standard je istoveten z: ISO 9177-3:2022
ICS:
01.100.40 Risalna oprema Drawing equipment
97.180 Razna oprema za dom in Miscellaneous domestic and
trgovino commercial equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
INTERNATIONAL ISO
STANDARD 9177-3
Second edition
2022-01
Mechanical pencils for technical
drawings —
Part 3:
Black leads — Bending strengths of
HB leads
Porte-mines pour le dessin technique —
Partie 3: Mines graphite — Résistance à la flexion des mines HB
Reference number
© ISO 2022
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
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Bending strength . 1
4.1 General . 1
4.2 Bending strength of HB leads for mechanical pencils . 1
5 Test method . 2
6 Test report . 3
Bibliography . 4
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).
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 I
...
INTERNATIONAL ISO
STANDARD 9177-3
Second edition
2022-01
Mechanical pencils for technical
drawings —
Part 3:
Black leads — Bending strengths of
HB leads
Porte-mines pour le dessin technique —
Partie 3: Mines graphite — Résistance à la flexion des mines HB
Reference number
© ISO 2022
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
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Bending strength . 1
4.1 General . 1
4.2 Bending strength of HB leads for mechanical pencils . 1
5 Test method . 2
6 Test report . 3
Bibliography . 4
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).
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 Barri
...
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