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  • BS 949-2(1992) : 1992

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    SCREWING TAPS - SPECIFICATION FOR UNIFIED GROUND THREAD TAPS - MANUFACTURING TOLERANCES

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    Published date:  23-11-2012

    Publisher:  British Standards Institution

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    Table of Contents - (Show below) - (Hide below)

    Committees responsible
    Foreword
    Specification
    1. Scope
    2. References
    3. Right-hand and left-hand threads
    4. Tolerance classes of taps
    5. Dimensions and manufacturing tolerances of the
         threaded portion
    6. Marking
    Annexes
    A. (informative) Bases of calculation of the
         tolerances on the threaded portion of taps for
         Unified threads
    B. (informative) Example of calculation of the
         dimensions of the threaded portion of a tap
    C. (normative) Taps for BSW, BSF and BA threads
         (obsolescent)
    Tables
    1. Formulae for limits of tolerance for ground thread
         taps for Unified threads
    2. Dimensions and manufacturing tolerances for the
         threaded portion of UNC taps
    3. Dimensions and manufacturing tolerances for the
         threaded portion of UNF taps
    4. Tolerances on cumulative pitch for ground thread
         taps for Unified threads
    A.1 Values of elements based on pitch in basic formulae
         for taps for Unified threads
    A.2 Values of elements based on nominal diameter in
         basic formulae for taps for Unified threads
    A.3 Values of elements used in calculating the minor
         diameter from a measured value of the pitch
         diameter of a tap for Unified threads
    A.4 Tolerances on thread angle of taps for Unified
         threads
    B.1 Calculation of the dimensions of a ground thread
         5/8 - 11 UNC tap, class 2
    C.1 Dimensions and manufacturing tolerances for the
         threaded portion of BSW taps
    C.2 Dimensions and manufacturing tolerances for the
         threaded portion of BSF taps
    C.3 Dimensions and manufacturing tolerances for the
         threaded portion of BA taps, class 2
    C.4 Formulae for limits of tolerance for taps for BSW,
         BSF and BA threads
    C.5 Values of elements based on pitch in basic formulae
         for BSW and BSF threads
    C.6 Values of elements based on nominal diameter in
         basic formulae for BSW and BSF threads
    C.7 Values of elements used in calculating the minor
         diameter from a measured value of the pitch
         diameter of a tap for a BSW or BSF thread
    C.8 Values of elements used in calculating the minor
         diameter from a measured value of the pitch
         diameter of a tap for a BA thread
    Figures
    1. Relationship of tap classes to nut tolerances
    A.1 Minimum values of tap major diameter d
    A.2 Tap minor diameter d1
    List of references

    Abstract - (Show below) - (Hide below)

    Specifies tolerances and dimensions for screwing taps for various threads. Coverage includes: right-hand and left-hand threads; tolerance classes of taps; marking; dimensions and manufacturing tolerances of the threaded portion. Also includes annexes, tables and diagrams.

    General Product Information - (Show below) - (Hide below)

    Committee MTE/5
    Development Note Supersedes BS 949-2(1979) (12/2004) Supersedes 90/79112 DC (10/2005) Reviewed and confirmed by BSI, January 2011. (12/2010)
    Document Type Standard
    Publisher British Standards Institution
    Status Current
    Supersedes

    Standards Referenced By This Book - (Show below) - (Hide below)

    BS 949-3(1993) : 1993 SCREWING TAPS - SPECIFICATION FOR PIPE THREAD TAPS
    BS 3409-2(1966) : 1966 SPECIFICATION FOR THE TAPPING OF HOLES TO RECEIVE WIRE THREAD INSERTS (UNC AND UNF THREADS) - DIAMETERS BELOW 1/4 IN

    Standards Referencing This Book - (Show below) - (Hide below)

    BS 949-4(1990) : 1990 SCREWING TAPS - SPECIFICATION FOR METRIC GROUND THREAD TAPS: MANUFACTURING TOLERANCES
    BS 949-3(1982) : 1982 SCREWING TAPS - SPECIFICATION FOR TAPS FOR PIPE THREADS (G SERIES, Rp SERIES AND Rc SERIES)
    BS 93(1951) : 1951 SPECIFICATION FOR BRITISH ASSOCIATION (B.A.) SCREW THREADS WITH TOLERANCES FOR SIZES 0 B.A. TO 16 B.A.
    BS 1580-3(1965) : 1965 SPECIFICATION FOR UNIFIED SCREW THREADS - DIAMETERS BELOW 1/4 IN AND LARGER
    BS 1580-1&2(1962) : 1962 SPECIFICATION FOR UNIFIED SCREW THREADS - DIAMETERS 1/4 INCH AND LARGER
    BS 84:1956 SPECIFICATION FOR PARALLEL SCREW THREADS OF WHITWORTH FORM
    BS 949-5(1990) : 1990 SCREWING TAPS - NOMENCLATURE AND TERMINOLOGY
    BS 949-1(1992) : 1992 SCREWING TAPS - PART 1: SPECIFICATION OF GENERAL DIMENSIONS
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