Cross arm 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 cross arm bolts up to 1-1/2″ in diameter. Cross arm 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
12 0.515 34 0.750 0.725 1.061 0.995 2164 0.348 0.308
58 0.642 1516 0.938 0.906 1.326 1.244 2764 0.444 0.400
34 0.768 118 1.125 1.088 1.591 1.494 12 0.524 0.476
78 0.895 1516 1.312 1.269 1.856 1.742 1932 0.620 0.568
1 1.022 112 1.500 1.450 2.121 1.991 2132 0.684 0.628
118 1.149 11116 1.688 1.631 2.386 2.239 34 0.780 0.720
114 1.277 178 1.875 1.812 2.652 2.489 2732 0.876 0.812
138 1.404 2116 2.062 1.994 2.917 2.738 2932 0.940 0.872
112 1.531 214 2.250 2.175 3.182 2.986 1 1.036 0.964
134* 2916 1316
2* 21516 1516

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.