Flat Head                                             ANSI/ASME B18.6.3 1972
Nominal Size	Head Dimensions			Slot Dimensions				Recess Dimensions			Protrusion Above Gaging Dia.		Gaging Dia.	Driver Size
	Diameter		Height	Width		Depth		Dia.	Depth	Width
	Max	Min	Ref	Max	Min	Max	Min	Ref	Ref	Ref	Max	Min
0	.119	.099	.035	.023	.016	.015	.010	.062	.035	.014	.026	.016	.078	0
1	.146	.123	.043	.026	.019	.019	.012	.070	.043	.015	.028	.016	.101	0
2	.172	.147	.051	.031	.023	.023	.015	.095	.055	.017	.029	.017	.124	1
3	.199	.171	.059	.035	.027	.027	.017	.100	.060	.018	.031	.018	.148	1
4	.225	.195	.067	.039	.031	.030	.020	.121	.081	.018	.032	.019	.172	1
5	.252	.220	.075	.043	.035	.034	.022	.147	.074	.027	.034	.020	.196	2
6	.279	.244	.083	.048	.039	.038	.024	.167	.094	.029	.036	.021	.220	2
8	.332	.292	.100	.054	.045	.045	.029	.182	.109	.030	.039	.023	.267	2
10	.385	.340	.116	.060	.050	.053	.034	.197	.124	.032	.042	.025	.313	2
12	.438	.389	.132	.067	.056	.060	.039	.261	.144	.035	.045	.027	.362	3
1/4	.507	.452	.153	.075	.064	.070	.046	.276	.159	.036	.050	.029	.424	3
5/16	.635	.568	.191	.084	.072	.088	.058	.358	.205	.061	.057	.034	.539	4
3/8	.762	.685	.230	.094	.081	.106	.070	.386	.234	.065	.065	.039	.653	4
1/2	.875	.775	.223	.106	.091	.103	.065	.417	.265	.069	.081	.049	.739	4