ISO 2903:2016 pdf free
ISO 2903:2016 pdf free.ISO metric trapezoidal screw threads – Tolerances
This document specifies a tolerance system for metric trapezoidal screw threads in accordance with ISO 2902. The tolerances refer to the design profile in accordance with ISO 2901.
The tolerance system does not apply to trapezoidal screw threads with special requirements on axial displacement, for example, machine tool lead and feed screws and nuts.
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 965-1, ISO general purpose metric screw threads一Tolerances一Part 1: Principles and basic data
ISO 2901, ISO metric trapezoidal screw threads一Basic and design profiles
ISO 2902, ISO metric trapezoidal screw threads一General plan
For the purposes of this document, the terms and definitions given in ISO 5408 apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
一IEC Electropedia: available at http://www.electropedia.org/
一ISO Online browsing platform: available at http://www.iso.org/obp
The system is based on the tolerance system for ISO general-purpose metric screw threads of ISO 965-1.
The following tolerance positions are standardized for the pitch diameters.
一For internal threads: H with zero fundamental deviation (EI). See Figure 1.
一For external threads: C and e with negative fundamental deviation (es). See Figure 2.
The tolerance position for the minor diameter (D1) and the major diameter (D4) of the internal threads is always H, i.e. with zero fundamental deviation (EI).
The tolerance position for the major diameter (d) and minor diameter (d3) of the external threads is in all cases h, i.e. with zero fundamental deviation (es), and it is independent of the tolerance positions of the pitch diameter.
The fundamental deviations for the pitch diameters of internal and external threads are given in Table 1.ISO 2903 pdf free download.
