Dimensions of ASME B18.9 No 3 Square Neck Countersunk Head Plow Bolts

Nominal or Basic Bolt Diameter, D	Diameter of Full Size Body, E		Diameter of Head, A			Maximum Feed Thickness, F	Depth of Square and Head, S		Width of Square, B		Maximum Radius on Corners of Square, R
	Max	Min	Max	Min. Sharp	ABS Min with flat		Max	Min (Basic)	Max	Min (Basic)
Regular Head
5/16	0.312	0.299	0.605	0.578	0.563	0.025	0.269	0.243	0.325	0.313	0.031
3/8	0.375	0.36	0.708	0.671	0.656	0.031	0.312	0.281	0.387	0.375	0.047
7/16	0.438	0.421	0.826	0.781	0.766	0.036	0.364	0.328	0.45	0.438	0.047
1/2	0.5	0.483	0.945	0.89	0.875	0.042	0.417	0.375	0.515	0.5	0.047
9/16	0.592	0.544	1.045	1	0.969	0.045	0.461	0.416	0.578	0.563	0.078
5/8	0.657	0.606	1.147	1.094	1.063	0.05	0.506	0.456	0.64	0.625	0.078
3/4	0.782	0.729	1.303	1.25	1.219	0.05	0.541	0.491	0.765	0.75	0.078
7/8	0.938	0.853	1.512	1.469	1.406	0.063	0.626	0.563	0.906	0.875	0.094
1	1.062	0.976	1.7	1.656	1.594	0.063	0.69	0.627	1.031	1	0.094
Repair Head
5/16	0.312	0.299	0.556	0.531	0.516	0.02	0.232	0.212	0.325	0.313	0.031
3/8	0.375	0.36	0.659	0.624	0.609	0.025	0.272	0.247	0.387	0.375	0.047
7/16	0.438	0.421	0.779	0.734	0.719	0.03	0.324	0.294	0.45	0.438	0.047
1/2	0.5	0.483	0.898	0.843	1.828	0.035	0.375	0.34	0.515	0.5	0.047
9/16	0.592	0.544	1.002	0.953	0.922	0.04	0.423	0.383	0.578	0.563	0.078
5/8	0.657	0.606	1.096	1.047	1.016	0.04	0.458	0.418	0.64	0.625	0.078
3/4	0.782	0.729	1.252	1.203	1.172	0.04	0.493	0.453	0.765	0.75	0.078
7/8	0.938	0.853	1.465	1.422	1.359	0.05	0.573	0.523	0.906	0.875	0.094
1	1.062	0.976	1.653	1.609	1.547	0.05	0.637	0.587	1.031	1	0.094

Notes :

• Where specifying nominal size in decimals, zeros preceding the decimals and in the fourth decimal place shall be omitted.
• This size is not recommended.
• The letter "R" shall be shown on top of the repair head to distinguish it from the regular head bolt.