Do ASTM and SAE Grades Require a Specific Head Style?

Structural BoltWhen selecting an ASTM grade of fastener for a particular application, the chemical and mechanical requirements are normally considered first, but there are some fastener specifications that require a certain head style as well.  Below is a chart showing some common ASTM grades and whether or not they have requirements for the pattern of forged head.  It is important to keep in mind that this chart only specifies requirements in regards to headed bolts.

Specification Grade Specified Head Configuration
ASTM A307 A Standard Hex
B Heavy Hex
ASTM F3125 A325 Heavy Hex Structural
A490
ASTM A449 Standard Hex
ASTM A193 B7 Heavy Hex
B8
B8M
ASTM A320 L7 Heavy Hex
B8
B8M
ASTM A354 BC Standard Hex
BD
ASTM F1554 Grade 36 Unspecified
Grade 55
Grade 105
ASTM F593 Alloy Group 1 Standard Hex
Alloy Group 2
SAE J429 Grade 2 Standard Hex
Grade 5
Grade 8
Head styles are unless otherwise specified.

As you can see, most of the grades shown in this chart have a head style for which they are normally specified, however in most cases this can be changed if needed.  Many of these ASTM grades may also allow for other configurations such as bent anchor bolts and straight rods.

As you can see, most of the grades shown in this chart have a head style that they are normally specified as, however in most cases this can be changed if needed.    Many of these ASTM grades may also allow for other configurations such as bent anchor bolts and straight rods.

The following are two charts detailing the dimensions for a standard hex head versus a heavy hex head:

Hex Bolt Dimensions

Click table to show drawing
Bolt Diameter D F C H
Body Diameter Width Across Flats Width Across Corners Height
Max Basic Max Min Max Min Basic Max Min
12 0.515 34 0.750 0.725 0.866 0.826 1132 0.364 0.302
58 0.642 1516 0.938 0.906 1.083 1.033 2764 0.444 0.378
34 0.768 118 1.125 1.088 1.299 1.240 12 0.524 0.455
78 0.895 1516 1.312 1.269 1.516 1.447 3764 0.604 0.531
1 1.022 112 1.500 1.450 1.732 1.653 4364 0.700 0.591
118 1.149 11116 1.688 1.631 1.949 1.859 34 0.780 0.658
114 1.277 178 1.875 1.812 2.165 2.066 2732 0.876 0.749
138 1.404 2116 2.062 1.994 2.382 2.273 2932 0.940 0.810
112 1.531 214 2.250 2.175 2.598 2.480 1 1.036 0.902
158 1.658 2716 2.438 2.356 2.815 2.616 1332 1.116 0.978
134 1.785 2-5/8 2.625 2.538 3.031 2.893 1532 1.196 1.054
178 1.912 21316 2.812 2.719 3.248 3.099 114 1.276 1.130
2 2.039 3 3.000 2.900 3.464 3.306 11132 1.388 1.175
214 2.305 338 3.375 3.262 3.897 3.719 112 1.548 1.327
212 2.559 334 3.750 3.625 4.330 4.133 12132 1.708 1.479
Dimensions per ASME B18.2.1 2010

Heavy Hex Dimensions

Click table to show drawing
Bolt Diameter D F C H
Body Diameter Width Across Flats Width Across Corners Height
Max Basic Max Min Max Min Basic Max Min
12 0.515 78 0.875 0.850 1.010 0.969 1132 0.364 0.302
58 0.642 1116 1.062 1.031 1.227 1.175 2764 0.444 0.378
34 0.768 114 1.250 1.212 1.443 1.383 12 0.524 0.455
78 0.895 1716 1.438 1.394 1.660 1.589 3764 0.604 0.531
1 1.022 158 1.625 1.575 1.876 1.796 4364 0.700 0.591
118 1.149 11316 1.812 1.756 2.093 2.002 34 0.780 0.658
114 1.277 2 2.00 1.938 2.309 2.209 2732 0.876 0.749
138 1.404 2316 2.188 2.119 2.526 2.416 2932 0.940 0.810
112 1.531 238 2.375 2.300 2.742 2.622 1 1.036 0.902
158 1.658 2916 2.562 2.481 2.959 2.829 1332 1.116 0.978
134 1.785 234 2.750 2.662 3.175 3.035 1532 1.196 1.054
178 1.912 21516 2.938 2.844 3.392 3.242 114 1.276 1.130
2 2.039 318 3.125 3.025 3.608 3.449 11132 1.388 1.175
214 2.305 312 3.500 3.388 4.041 3.862 112 1.548 1.327
212 2.559 378 3.875 3.750 4.474 4.275 12132 1.708 1.479

Dimensions per ASME B18.2.1 2010

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