This Standard was approved by letter ballot of the B18 Committee on July 2, 1979, and was subsequently approved by the secretariats and submitted to the American National Standards Institute for designation as an American National Standard. This was granted on December 6, 1979. In March 2007, B18 Subcommittee 2 decided to start a major revision of the Standard. The scope was revised to include the range of nuts from M12 through M100, dimensional differences were coordinated to the extent possible with ISO 4775, the referenced standards were specifically identified, the terminology was referenced specifically to ASME B18.12, symbols specifying geometric characteristics were made in accordance with ASME Y14.5, stainless steel and nonferrous nuts were conformed to the requirements of ASTM F 836M, stainless steel and nonferrous nuts were marked to identify the property class and manufacturer in accordance with requirements specified in ASTM F 836M or ASTM F 467M, acceptability of nuts was determined in accordance with ASME B18.18.2, a reference was made for the recommended B18 (PIN) for metric heavy hex nuts and was included in ASME B18.24, a workmanship reference to ASTM F 812/F 812M was added, Table 1 was enhanced to include symbols specifying geometric characteristics per ASME Y14.5, the table in Nonmandatory Appendix A was added to
.assist in determining the dimensional differences between ASME B18.2.4.6M and ISO 4775, and Appendix 1 and Table 2 were removed
 

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