Hex Head Machine Bolt

Hex head machine bolts are used for fastening pole line hardware and line construction specialty products to crossarm poles and other structures as well as attaching the wooden crossarms to the pole. Hex head machine bolts have an added semi-cone point and a thread length unique to pole line fasteners depending on the length of the bolts. Hex head machine bolts also have a hex nut assembled.

Hex Machine Bolt Drawing

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
1⁄2 0.515 3⁄4 0.750 0.725 0.866 0.826 11⁄32 0.364 0.302
5⁄8 0.642 15⁄16 0.938 0.906 1.083 1.033 27⁄64 0.444 0.378
3⁄4 0.768 11⁄8 1.125 1.088 1.299 1.240 1⁄2 0.524 0.455
7⁄8 0.895 15⁄16 1.312 1.269 1.516 1.447 37⁄64 0.604 0.531
1 1.022 11⁄2 1.500 1.450 1.732 1.653 43⁄64 0.700 0.591
11⁄8 1.149 111⁄16 1.688 1.631 1.949 1.859 3⁄4 0.780 0.658
11⁄4 1.277 17⁄8 1.875 1.812 2.165 2.066 27⁄32 0.876 0.749
13⁄8 1.404 21⁄16 2.062 1.994 2.382 2.273 29⁄32 0.940 0.810
11⁄2 1.531 21⁄4 2.250 2.175 2.598 2.480 1 1.036 0.902
15⁄8 1.658 27⁄16 2.438 2.356 2.815 2.616 13⁄32 1.116 0.978
13⁄4 1.785 2-5/8 2.625 2.538 3.031 2.893 15⁄32 1.196 1.054
17⁄8 1.912 213⁄16 2.812 2.719 3.248 3.099 11⁄4 1.276 1.130
2 2.039 3 3.000 2.900 3.464 3.306 111⁄32 1.388 1.175
21⁄4 2.305 33⁄8 3.375 3.262 3.897 3.719 11⁄2 1.548 1.327
21⁄2 2.559 33⁄4 3.750 3.625 4.330 4.133 121⁄32 1.708 1.479
Dimensions per ASME B18.2.1

Standard Thread Lengths

*Bolts shorter and/or smaller than those listed in the table shall have minimum thread lengths in accordance with American National Standard for Square and  Hex Bolts and Screws, B18.2.1*
Diameters Bolt length Thread length
  • 3/8"
  • 1/2"
  • 5/8"
  • 3/4"
  • 7/8"
  • 1"
 4" up to less than 8" 3"
  • 3/8"
  • 1/2"
  • 5/8"
  • 3/4"
  • 7/8"
  • 1"
  • 1-1/4"
 8" up to less than 12" 4"
  • 3/8"
  • 1/2"
  • 5/8"
  • 3/4"
  • 7/8"
  • 1"
  • 1-1/4"
 12" and over 6"