ASME B18.5 Countersunk Bolts and Slotted Countersunk Bolts

                                                                                                                                               

Nominal Sizea		Body Diameter, E		Head Diameter, A			Flat on Min Dia.,Head, Fb	Head Height, H		Slot Width, J		Slot Depth, T
		Max	Min	Max Edge Sharp	Min Edge Sharp	Absolute Min Edge Rounded or Flat	Max	Maxc	Mind	Max	Min	Max	Min
ASME B18.5 - 1⁄4	0.25	0.26	0.237	0.493	0.477	0.445	0.018	0.15	0.131	0.075	0.064	0.068	0.045
ASME B18.5 - 5⁄16	0.3125	0.324	0.298	0.618	0.598	0.558	0.023	0.189	0.164	0.084	0.072	0.086	0.057
ASME B18.5 - 3⁄8	0.375	0.388	0.36	0.74	0.715	0.668	0.027	0.225	0.196	0.094	0.081	0.103	0.068
ASME B18.5 - 7⁄16	0.4375	0.452	0.421	0.803	0.778	0.726	0.03	0.226	0.196	0.094	0.081	0.103	0.068
ASME B18.5 - 1⁄2	0.5	0.515	0.483	0.935	0.905	0.845	0.035	0.269	0.233	0.106	0.091	0.103	0.068
ASME B18.5 - 5⁄8	0.625	0.642	0.605	1.169	1.132	1.066	0.038	0.336	0.292	0.133	0.116	0.137	0.091
ASME B18.5 - 3⁄4	0.75	0.768	0.729	1.402	1.357	1.285	0.041	0.403	0.349	0.149	0.131	0.171	0.115
ASME B18.5 - 7⁄8	0.875	0.895	0.852	1.637	1.584	1.511	0.042	0.47	0.408	0.167	0.147	0.206	0.138
ASME B18.5 - 1	1	1.022	0.976	1.869	1.81	1.735	0.043	0.537	0.466	0.188	0.166	0.24	0.162
ASME B18.5 - 1 1⁄8	1.125	1.149	1.098	2.104	2.037	1.962	0.043	0.604	0.525	0.196	0.178	0.257	0.173
ASME B18.5 - 1 1⁄4	1.25	1.277	1.223	2.337	2.262	2.187	0.043	0.671	0.582	0.211	0.193	0.291	0.197
ASME B18.5 - 1 3⁄8	1.375	1.404	1.345	2.571	2.489	2.414	0.043	0.738	0.641	0.226	0.208	0.326	0.22
ASME B18.5 - 1 1⁄2	1.5	1.531	1.47	2.804	2.715	2.64	0.043	0.805	0.698	0.258	0.24	0.36	0.244
a Where specifying size in decimals, zeros preceding decimal and in fourth decimal place are omitted. b Flat on minimum diameter head calculated on minimum sharp and absolute minimum head diameters and 82° head angle. c Maximum head height calculated on maximum sharp head diameter, basic bolt diameter, and 78° head angle. d Minimum head height calculated on minimum sharp head diameter, basic bolt diameter, and 82° head angle. All dimensions are given in inches. For thread information and method of bolt designation see foonotes to previous table. Heads are unslotted unless otherwise specified. For slot dimensions see Table 1 in Slotted Head Cap Screw section.