BS ISO 2904:2020 pdf download

BS ISO 2904:2020 pdf download.ISO metric trapezoidal screw threads-Basic dimensions.
National foreword
BS ISO 2904 is the UK implementation of ISO 2904:2020. Together with BS ISO 2901:2016. BS ISO 2902:2016. BS ISO 2903:2016 and BS ISO 965-1:2013, it supersedes BS 5346:1976. which is withdrawn.
The UK participation in its preparation was entrusted to Technical Committee FME/9, Fasteners.
A list of organizations represented on this committee can be obtained on request to its secretary.
This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.
©BS ISO 2904 Institution 2020
Published by BSI Standards Limited 2020
ISBN 978 0 539 05340 1 ICS 21.040.10
Compliance with a British Standard cannot confer immunity from legal obligations.
BS ISO 2904 was published under the authority of the Standards Policy and Strategy Committee on 29 February 2020.
Amendments/corrigenda issued since publicationDate Text affected.
ISO (BS ISO 2904 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 BS ISO 2904 Electro technical Commission (IEC) on all matters of electro technical standardization.
1 Scope
BS ISO 2904 specifies the basic dimensions of ISO metric trapezoidal screw threads in accordance with ISO 2902. The values refer to the design profiles in accordance with ISO 2901.
BS ISO 2904 is chiefly applicable to traversing threads for traversing motion on machines, tools, etc. It can also be used for fastening threads.
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 5408, Screw threads — Vocabulary
4 Symbols
For the purposes of this document, the following symbols apply.
Di basic minor diameter of internal thread basic pitch diameter of internal thread
basic major diameter of internal thread
d basic major diameter of external thread (nominal diameterj
d2 basic pitch diameter of external thread
d3 basic minor diameter of external thread
P pitch
ac clearance at major and minor diameters
R1 radius on crest corners of external thread on design profile
R2 radius on root corners of internal and external threads on design profile
5 Basic dimensions
Basic dimensions shown in Figure 1 are given in Table 1.
The values of D1, D2, D4, d2 and d3, in Table 1, have been calculated from the following formulae and rounded to the third decimal place.BS-ISO-2904-2020

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