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Across Flats Dimensions of Hex Headed Bolts

Shaft Diameter	Maximum		Minimum
	Inches	mm	Inches	mm
10BA	0.117	2.97	0.114	2.90
SAE NO 2	0.125	3.18	0.120	3.05
9BA	0.131	3.33	0.128	3.25
8BA	0.152	3.86	0.149	3.79
7BA	0.172	4.37	0.169	4.29
SAE NO 3	0.187	4.75	0.181	4.59
SAE NO 4	0.187	4.75	0.181	4.59
SAE NO 5	0.187	4.75	0.181	4.59
6BA	0.193	4.90	0.189	4.80
5BA	0.220	5.59	0.216	5.49
BS 1/8"	0.220	5.59	0.216	5.49
4BA	0.248	6.30	0.243	6.17
BS 5/32"	0.245	6.30	0.243	6.17
SAE NO 6	0.250	6.35	0.244	6.20
SAE NO 8	0.250	6.35	0.244	6.20
3BA	0.282	7.16	0.277	7.04
SAE NO 10	0.312	7.92	0.305	7.75
SAE NO 12	0.312	7.92	0.305	7.75
5mm	0.315	8.00	0.300	7.64
2BA	0.324	8.23	0.319	8.10
BS 3/16"	0.324	8.23	0.319	8.10
1BA	0.365	9.27	0.360	9.14
6mm	0.394	10.00	0.379	9.64
0BA	0.413	10.49	0.408	10.36
SAE 1/4"	0.438	11.13	0.425	10.80
BS 1/4"	0.445	11.30	0.435	11.05
SAE 5/16"	0.500	12.70	0.484	12.29
8mm	0.512	13.00	0.495	12.57
BS 5/16"	0.525	13.34	0.515	13.08
SAE 3/8"	0.563	14.30	0.544	13.82
BS 3/8"	0.600	15.24	0.585	14.86
SAE 7/16"	0.625	15.87	0.603	15.32
10mm	0.669	17.00	0.652	16.57
BS 7/16"	0.710	18.03	0.695	17.65
12mm	0.748	19.00	0.727	18.48
SAE 1/2"	0.750	19.05	0.725	18.42
SAE 9/16"	0.812	20.62	0.798	20.27
BS 1/2"	0.820	20.82	0.800	20.32
BS 9/16"	0.920	23.37	0.900	22.86
SAE 5/8"	0.938	23.81	0.906	23.01
16mm	0.945	24.00	0.912	23.16
BS 5/8"	1.010	25.65	0.985	25.02
SAE 3/4"	1.125	28.58	1.088	27.64
20mm	1.181	30.00	1.148	29.16
BS 3/4"	1.200	30.48	1.175	29.85
BS 7/8"	1.300	33.02	1.270	32.26
SAE 7/8"	1.313	33.34	1.269	32.23
24mm	1.417	36.00	1.378	35.00
BS 1"	1.480	37.59	1.450	36.83
SAE 1"	1.500	38.10	1.450	36.83