Crossarm or machine bolts are used in the pole line industry. They have square heads and a semi-cone point and typically come with a square nut assembled. They are also typically hot-dip galvanized in order to protect the steel. We can manufacture crossarm bolts up to 1-1/2″ in diameter. Crossarm bolts follow the thread length guidelines used for pole line fasteners. More information about machine bolts is available on our educational microsite polelinefasteners.com.

Machine 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
1⁄2 0.515 3⁄4 0.750 0.725 1.061 0.995 21⁄64 0.348 0.308
5⁄8 0.642 15⁄16 0.938 0.906 1.326 1.244 27⁄64 0.444 0.400
3⁄4 0.768 11⁄8 1.125 1.088 1.591 1.494 1⁄2 0.524 0.476
7⁄8 0.895 15⁄16 1.312 1.269 1.856 1.742 19⁄32 0.620 0.568
1 1.022 11⁄2 1.500 1.450 2.121 1.991 21⁄32 0.684 0.628
11⁄8 1.149 111⁄16 1.688 1.631 2.386 2.239 3⁄4 0.780 0.720
11⁄4 1.277 17⁄8 1.875 1.812 2.652 2.489 27⁄32 0.876 0.812
13⁄8 1.404 21⁄16 2.062 1.994 2.917 2.738 29⁄32 0.940 0.872
11⁄2 1.531 21⁄4 2.250 2.175 3.182 2.986 1 1.036 0.964
13⁄4* 29⁄16 13⁄16
2* 215⁄16 15⁄16

Dimensions per ASME B18.2.1 1996

* ASME only defines head dimensions up to 1-1/2". Dimensions for 1-3/4 and 2" are approximate and not covered under the ASME dimensional specifications.

Video: Making of a Machine BoltTake a quick tour of our shop and follow an order of 7/8″ diameter square head machine bolts through the manufacturing process. This video includes shearing, pointing, hot forging, roll threading, and galvanizing. Find out what it takes to make an order of large, custom machine bolts. Find more of our videos, or subscribe to us at pdxbolt on YouTube

PoleLineFasteners.comVisit our educational website www.polelinefasteners.com for product specific information on headed pole line fasteners. You can also read the answers to frequently asked questions about pole line fasteners and hardware.