Abstact： ASME B18.2.1:2010 pdf download.Square, Hex, HeavyHex, and Askew HeadBolts and Hex, HeavyHex, Hex Flange, Lobed Head, and LagScrews (Inch Series). In 1991, it was recognized that 1118.2.1 required extensive revision to better meet the needs
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