Dimensions of Square Lag Screws

Nominal Size or Basic product Diameter	Body or Shoulder Diameter, E		Width Across Flats, F			Width Across Corners, G		Head Height, H			Minimum Shoulder Length, S	Radius of Fillet, R
	Max.	Min.	Basic	Max.	Min.	Max.	Min.	Basic	Max.	Min.		Max.	Min.
No. 10 0.1900	0.199	0.178	9/32	0.281	0.271	0.398	0.372	1/8	0.140	0.110	0.094	0.03	0.01
1/4 0.2500	0.260	0.237	3/8	0.375	0.362	0.530	0.498	11/64	0.188	0.156	0.094	0.03	0.01
5/16 0.3125	0.324	0.298	1/2	0.500	0.484	0.707	0.665	13/64	0.220	0.186	0.125	0.03	0.01
3/8 0.3750	0.388	0.360	9/16	0.562	0.544	0.795	0.747	1/4	0.268	0.232	0.125	0.03	0.01
7/16 0.4375	0.452	0.421	5/8	0.625	0.603	0.884	0.828	19/64	0.316	0.278	0.156	0.03	0.01
1/2 0.5000	0.515	0.482	3/4	0.750	0.725	1.061	0.995	21/64	0.348	0.308	0.156	0.03	0.01
5/8 0.6250	0.642	0.605	15/16	0.938	0.906	1.326	1.244	27/64	0.444	0.400	0.312	0.06	0.02
3/4 0.7500	0.768	0.729	1 1/8	1.125	1.088	1.591	1.494	1/2	0.524	0.476	0.375	0.06	0.02
7/8 0.8750	0.895	0.852	1 5/16	1.312	1.269	1.856	1.742	19/32	0.620	0.568	0.375	0.06	0.02
1 1.0000	1.022	0.976	1 1/2	1.500	1.450	2.121	1.991	21/32	0.684	0.628	0.625	0.09	0.03
1 1/8 1.1250	1.149	1.098	1 11/16	1.688	1.631	2.386	2.239	3/4	0.780	0.720	0.625	0.09	0.03
1 1/4 1.2500	1.277	1.223	1 7/8	1.875	1.812	2.652	2.489	27/32	0.876	0.812	0.625	0.09	0.03

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