This Standard covers the general and dimensional data for metric heavy hex structural bolts recognized as American National Standard. The inclusion of dimensional data in this Standard is not intended to imply that all of the sizes in conjunction with the various options described herein are stock production items. Consumers are requested to consult with manufacturers concerning lists of stock production heavy hex structural bolts. Heavy hex structural bolts purchased for Government use shall conform to this standard, and additionally to the requirements of Appendix III. B18.2.3.7M-1979 and B18.2.4.6M-2010 have been incorporated into B18.2.6Mâ??2012.