Dimensions of ASME B18.9 No 7 Reverse Key Round Countersunk Head Plow Bolts

Nominal or Basic Bolt Diameter, D	Diameter of Full Size Body, E		Diameter of Head, A			Maximum Feed Thickness, F	Head Height, S		Key Length, G
	Max	Min	Max	Min. Sharp	ABS Min with flat		Max	Min	Min	Max
Regular Head
5/16	0.312	0.299	0.592	0.578	0.563	0.025	0.233	0.208	0.185	0.2
3/8	0.375	0.36	0.661	0.64	0.625	0.031	0.239	0.208	0.187	0.202
7/16	0.438	0.421	0.776	0.749	0.734	0.036	0.282	0.246	0.227	0.242
1/2	0.5	0.483	0.892	0.859	0.844	0.042	0.328	0.286	0.267	0.282
9/16	0.592	0.544	1.021	0.984	0.969	0.045	0.383	0.388	0.321	0.336
5/8	0.657	0.606	1.121	1.078	1.063	0.05	0.414	0.364	0.348	0.363
3/4	0.782	0.729	1.277	1.234	1.219	0.05	0.44	0.39	0.39	0.39
Repair Head
5/16	0.312	0.299	0.554	0.546	0.531	0.02	0.201	0.181	0.158	0.173
3/8	0.375	0.36	0.623	0.609	0.594	0.025	0.207	0.182	0.158	0..173
7/16	0.438	0.421	0.738	0.718	0.703	0.03	0.25	0.22	0.199	0.214
1/2	0.5	0.483	0.853	0.828	0.813	0.035	0.295	0.26	0.239	0.254
9/16	0.592	0.544	0.984	0.953	0.938	0.04	0.352	0.312	0.293	0.308
5/8	0.657	0.606	1.077	1.046	1.031	0.04	0.378	0.338	0.321	0.336
3/4	0.782	0.729	1.234	1.203	1.188	0.04	0.404	0.364	0.347	0.362

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.