F3125 Dimensions

Since F3125 bolts are structural bolts and used in such specific applications they have some dimensional characteristics that are more strict than other grades. These dimensions include length tolerances, head dimensions, thread lengths, and length tolerances.

Structural bolts are required to have a full body diameter which limits the methods of threading the bolts in the manufacturing process. They also have shorter thread lengths than other bolts due to the nature of their application.

F3125 Available Sizes

F3125 bolts can only be ½”-1 ½” in diameter. Anything above or below this range would not follow the ASTM specification and would have to be moved to a different grade because it doesn’t exist.

A325T bolts are the exception to the standard requirements for thread lengths for A325 bolts. A325T bolts are fully threaded bolts. The threads start from the end and go to beneath the head.

F3125 Bolt Dimensions

Bolt Diameter	D	F			C		H			T
	Body Diameter	Width Across Flats			Width Across Corners		Height			Thread Length
	Max	Basic	Max	Min	Max	Min	Basic	Max	Min	Basic
¹⁄₂	0.515	⁷⁄₈	0.875	0.85	1.01	0.969	⁵⁄₁₆	0.323	0.302	1
⁵⁄₈	0.642	1¹⁄₁₆	1.062	1.031	1.227	1.175	²⁵⁄₆₄	0.403	0.378	1.25
³⁄₄	0.768	1¹⁄₄	1.25	1.212	1.443	1.383	¹⁵⁄₃₂	0.483	0.455	1.38
⁷⁄₈	0.895	1⁷⁄₁₆	1.438	1.394	1.66	1.589	³⁵⁄₆₄	0.563	0.531	1.5
1	1.022	1⁵⁄₈	1.625	1.575	1.876	1.796	³⁹⁄₆₄	0.627	0.591	1.75
1¹⁄₈	1.149	1¹³⁄₁₆	1.812	1.756	2.093	2.002	¹¹⁄₁₆	0.718	0.658	2
1¹⁄₄	1.277	2	2	1.938	2.309	2.209	²⁵⁄₃₂	0.813	0.749	2
1³⁄₈	1.404	2³⁄₁₆	2.188	2.119	2.526	2.416	²⁷⁄₃₂	0.878	0.81	2.25
1¹⁄₂	1.531	2³⁄₈	2.375	2.3	2.742	2.622	¹⁵⁄₁₆	0.974	0.902	2.25

Dimensions per ASME B18.2.6 2011