Part2:Specificationforselectedlimits ofsize
ICS 21.040.10
NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW
BSI 2007
ISBN 978 0 580 57925 7
Publication history
First published June 1965Second edition December 1966 Thid edition December 1981Fourth edition November 2007
Publishing and copyright information
Amendments issued since publication
The BSI copyright notice displayed in this document indicates when the document was last issued.
The following BSI references relate to the work on this standard:Draft for ment 07/ DC Committee reference FME/9
Text affeeted
Contents
Foreword ii
1 Scope12 Normative references13 4 Terms and definitions 1 Designation 25 Requirements 2
Annexes
Bibliography 42
List of tables
Summary of pages
Annex A (normative) Fundamental deviations tolerances and limits of size for additional tolerance classes for aerospace use 39
Table 1 ISO metric screw threads Limits and tolerances for finished uncoated threads for normal length of engagement 3Table A.1 ISO metric screw threads Limits and tolerances forfinished uncoated threads for normal length of engagement for aerospace use 40
This document prises a front cover an inside front cover pages i and i pages 1 to 42 an inside back cover and a back cover.
Foreword
Publishing information
This part of BS 3643 is published by BSI and came into effecton 30 November 2007. It was prepared by Submittee SFTSE/1 Screus andfasteners technical specification mittee under the authority of Technical Committee FME/9 Nuts bolts cnd accessories.A list of organizations represented on this mittee can be obtainedon request to its secretary.
Supersession
This part of BS 3643 supersedes BS 3643-2:1981 which is withdrawn.
Relationshipwithotherpublications
BS 3643 consists of the following parts:
Part 1: Principles and basic data;*Part 2: Specification for selected limits of size.
Information about this document
This part of BS 3643 has been revised to bring it up to date.
Hazard warnings
WARNING. Attention is drawn to the fact that with the different screw thread forms available there is the possibility of a mismatch which is potentially hazardous. It is the responsibility of the designerof the end product to ensure that this possibility is reduced to a minimum. For further information on mismatches of screw threadsystems see PD 6494.
Presentational conventions
The provisions of this standard are presented in roman (i.e. upright)auxiliary verb is *shall'. type. Its requirements are expressed in sentences in which the principal
Commentary explanation and general informative material ispresented in smailer italic type and does not constitute anormative element.
Contractual and legal considerations
This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.
Compliance with a British Standard cannot confer immunityfrom legal obligations.
1Scope
2Normativereferences
3Termsanddefinitions
This part of this BS 3643 specifies the fundamental deviations tolerances and limits of size for the tolerance classes 4H 5H 6H and 7H for internal threads and 4h 6g and Sg for external threads where:o apeudoudde
• a coarse pitch series with the range 1 mm to 68 mm diameter;•a fine pitch series with the range 1 mm to 33 mm diameter;a constant pitch series with the range 8 mm to 300 mm diameter.
tolerances and limits of size for tolerance class 4H for internal threads For certain diameter/pitch binations the fundamental deviations and tolerance classes 6h and 4g for external threads primarily foraerospace use are specified in Annex A.
The following referenced documents are indispensable for the application of this document. For dated references only the editioncited applies. For undated references the latest edition of thereferenced document (including any amendments) applies.
BS 3643-1:2007 ISO metric screw threads Principles and basicdata
in BS 3643-1:2007 apply. For the purposes of this part of BS 3643 the terms and definitions given
