Dimensions of ASME B18.2.1 Heavy Hex Bolts

Nominal Size or Basic product Diameter		Full Size Body Diameter, E		Width Across Flats, F			Width Across Corners, G		Head Height, H			Radius of Fillet, R		Thread Length for Bolt Lengths, LT
														6 in. and Shorter	Over 6 in.
		Max	Min	Basic	Max	Min	Max	Min	Basic	Max	Min	Max	Min	Nom	Nom
3/8	0.3750	0.388	0.360	11/6	0.688	0.669	0.794	0.763	1/4	0.268	0.226	0.03	0.01	1.000	1.250
1/2	0.5000	0.515	0.482	7/8	0.875	0.850	1.010	0.969	11/32	0.364	0.302	0.03	0.01	1.250	1.500
5/8	0.6250	0.642	0.605	11/16	1.062	1.031	1.227	1.175	27/64	0.444	0.378	0.06	0.02	1.500	1.750
3/4	0.7500	0.768	0.729	1 1/4	1.250	1.212	1.443	1.383	1/2	0.524	0.455	0.06	0.02	1.750	2.000
7/8	0.8750	0.895	0.852	1 7/16	1.438	1.394	1.660	1.589	37/64	0.604	0.531	0.06	0.02	2.000	2.250
1	1.000	1.022	0.976	1 5/8	1.625	1.575	1.876	1.796	43/64	0.700	0.591	0.09	0.03	2.250	2.500
1 1/8	1.1250	1.149	1.098	1 13/16	1.812	1.756	2.093	2.002	3/4	0.780	0.658	0.09	0.03	2.500	2.750
1 1/4	1.2500	1.277	1.223	2	2.000	1.938	2.309	2.209	27/32	0.876	0.749	0.09	0.03	2.750	3.000
1 3/8	1.3750	1.404	1.345	2 3/16	2.188	2.119	2.526	2.416	29/32	0.940	0.810	0.09	0.03	3.000	3.250
1 1/2	1.5000	1.531	1.470	2 3/8	2.375	2.300	2.742	2.622	1	1.036	0.902	0.09	0.03	3.250	3.500
1 5/8	1.6250	1.658	1.591	2 9/16	2.562	2.481	2.959	2.829	1 3/32	1.116	0.978	0.09	0.03	3.500	3.750
1 3/4	1.7500	1.785	1.716	2 3/4	2.750	2.662	3.175	3.035	1 5/32	1.196	1.054	0.12	0.04	3.750	4.000
1 7/8	1.8750	1.912	1.839	2 15/16	2.938	2.844	3.392	3.242	1 1/4	1.276	1.130	0.12	0.04	4.000	4.250
2	2.000	2.039	1.964	3 1/8	3.125	3.025	3.608	3.449	1 11/32	1.388	1.175	0.12	0.04	4.250	4.500
2 1/4	2.2500	2.305	2.214	3 1/2	3.500	3.388	4.041	3.862	1 1/2	1.548	1.327	0.19	0.06	4.750	5.000
2 1/2	2.5000	2.559	2.461	3 7/8	3.875	3.750	4.474	4.275	1 21/32	1.708	1.479	0.19	0.06	5.250	5.500
2 3/4	2.7500	2.827	2.711	4 1/4	4.250	4.112	4.907	4.688	1 13/16	1.869	1.632	0.19	0.06	5.750	6.000
3	3.000	3.081	2.961	4 5/8	4.625	4.475	5.340	5.102	2	2.060	1.815	0.19	0.06	6.250	6.500

Dimensions of Screw Threads

Nomianal Size or Basic product Diameter		Threads per inch.	Major Diameter		Root Diameter		Length Tolerance
			Max.	Min.	Max.	Min.	≥ 6 in.	> 6 in.
No. 10	0.190	11	0.199	0.178	0.122	0.107	±0.12	±0.25
1/4	0.250	10	0.260	0.237	0.177	0.160	±0.12	±0.25
5/16	0.312	9	0.324	0.298	0.228	0.210	±0.12	±0.25
3/8	0.375	7	0.388	0.360	0.268	0.250	±0.12	±0.25
1/2	0.500	6	0.515	0.482	0.374	0.354	±0.12	±0.25
5/8	0.625	5	0.642	0.605	0.473	0.453	±0.25	±0.25
3/4	0.750	4 1/2	0.768	0.729	0.582	0.562	±0.25	±0.25
7/8	0.875	4	0.895	0.852	0.686	0.665	±0.25	±0.25
1	1.000	3 1/2	1.022	0.976	0.784	0.760	±0.25	±0.25
1 1/8	1.125	3 1/4	1.149	1.100	0.892	0.867	±0.25	±0.25
1 1/4	1.250	3 1/4	1.277	1.223	1.017	0.987	±0.25	±0.25