Hex Head Cap Screw Dimensions

Hex Head Cap Screw Dimensions are a fundamental reference for engineers, fabricators, and procurement professionals working with heavy-duty fasteners. On this page you’ll find a detailed chart from Atlanta Rod and Manufacturing covering body diameter, across-the-flats, head height, and thread-length specifications for each nominal size of hex head cap screw. Whether you’re verifying compliance to standards or selecting the correct size for structural applications, this guide delivers the precise, engineering-grade data you need.

Diameter (D)	Body Diameter (D)		Across the Flats (F)		Across the Corners (C)		Head Height (H)		Thread Lengths (T)
	MAX	MIN	MAX	MIN	MAX	MIN	MAX	MIN	< 6”	> 6”
1/2	0.515	0.482	0.875	0.85	1.01	0.969	0.364	0.302	1.25	1.5
5/8	0.642	0.605	1.062	1.031	1.227	1.175	0.444	0.378	1.5	1.75
3/4	0.768	0.729	1.25	1.212	1.443	1.383	0.524	0.455	1.75	2
7/8	0.895	0.852	1.438	1.394	1.66	1.589	0.604	0.531	2	2.25
1	1.022	0.976	1.625	1.575	1.876	1.796	0.7	0.591	2.25	2.5
1 1/8	1.149	1.098	1.812	1.756	2.093	2.002	0.78	0.658	2.5	2.75
1 1/4	1.277	1.223	2	1.938	2.309	2.209	0.876	0.749	2.75	3
1 3/8	1.404	1.345	2.188	2.119	2.526	2.416	0.94	0.81	3	3.25
1 1/2	1.531	1.47	2.375	2.3	2.742	2.622	1.036	0.902	3.25	3.5
1 3/4	1.785	1.716	2.75	2.662	3.175	3.035	1.196	1.054	3.75	4
2	2.039	1.964	3.125	3.025	3.608	3.449	1.388	1.175	4.25	4.5
2 1/4	2.305	2.214	3.5	3.388	4.041	3.862	1.548	1.327	4.75	5
2 1/2	2.559	2.461	3.875	3.75	4.474	4.275	1.708	1.479	5.25	5.5
2 3/4	2.827	2.711	4.25	4.112	4.907	4.688	1.869	1.632	5.75	6
3	3.081	2.961	4.625	4.475	5.34	5.102	2.06	1.815	6.25	6.5