Rationale

Currently, section 6.5.2.2 of ASTM E1820 states “The critical tolerances and suggested proportions of the clevis and pins (Note: for C(T) and DC(T) specimens) are given in Fig. 5.”. However, the current Fig. 5 does not provide any information about loading pins, and presents additional issues, some of which editorial. A completely revised Fig. 5, using the GD&T (Geometric Dimensioning & Tolerances) format, is presented in this ballot. Some new Notes, containing useful information and recommendations for the user, have also been added below the figure. In order to provide the missing information about loading pins and more useful details, two new sections are proposed for C(T) specimens (section A2.1.3) and DC(T) specimens (section A3.1.3) specimens, providing recommended/suggested dimensions and tolerances for specimen holes and loading pins. Recommended (not mandatory) dimensions and tolerances are provided in Table A2.1, as a function of specimen width W and specimen thickness B. The information in Table A2.1 prevents interferences between loading pins and specimen holes, and avoids excessively small machining tolerances in case of small specimens (thicknesses = 12.7 mm). This item was balloted five times at E08.07 subcommittee level between 2022 and 2024. During the last E08.07.05 meeting in Philadelphia (May 2024), members felt that it was sufficiently mature to move to combined main/sub level. All changes with respect to the current E1820-23b standard are highlighted using “Track Changes”.