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), 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 several times at E08.07 subcommittee level between 2022 and 2024. At the end of 2024, it was balloted at combined main/sub level, where several typos and errors were identified. These have been corrected in the revised version balloted here. All changes with respect to the current E1820-24 standard are highlighted using “Track Changes”.