Dimensions of ASME B18.31.5 Round Bend U Bolts

Pin Fields		Diameter D, and UNC Thread	Inside Length, L			Inside Width, C			Thread Length, T		Nominal Pipe Size
3,D	5, LCT		Basic	Max	Min	Basic	Max	Min	Max	Min
04	012	1/4 - 20	1.250	1.280	1.220	0.563	0.593	0.533	0.810	0.690	1/4
04	013	1/4 - 20	1.250	1.280	1.220	0.750	0.780	0.720	0.685	0.565	3/8
04	022	1/4 - 20	2.250	2.280	2.220	0.750	0.780	0.720	1.560	1.440	3/8
04	017	1/4 - 20	1.750	1.780	1.720	1.000	1.030	0.970	1.060	0.940	1/2
04	020	1/4 - 20	2.000	2.030	1.970	1.000	1.030	0.970	1.060	0.940	3/4
04	031	1/4 - 20	3.125	3.155	3.095	1.000	1.155	0.970	1.560	1.440	3/4
04	023	1/4 - 20	2.250	2.280	2.220	1.125	1.155	1.095	1.310	1.190	3/4
04	027	1/4 - 20	2.750	2.780	2.720	1.125	1.155	1.095	1.435	1.315	1
04	034	1/4 - 20	3.438	3.468	3.408	1.125	1.280	1.095	2.435	2.315	1
04	030	1/4 - 20	3.000	3.030	2.970	1.250	1.280	1.220	1.435	1.315	1 1/4
04	032	1/4 - 20	3.250	3.280	3.220	1.250	1.405	1.220	1.435	1.315	1 1/2
05	021	5/16 - 18	2.188	2.218	2.158	1.375	1.405	1.345	1.435	1.315	1/2
05	0222	5/16 - 18	2.188	2.218	2.158	1.375	1.530	1.345	1.060	0.940	3/4
05	023	5/16 - 18	2.188	2.218	2.158	1.500	1.530	1.470	1.060	0.940	1
05	026	5/16 - 18	2.688	2.718	2.658	1.500	1.780	1.470	1.185	1.065	1 1/4
05	045	5/16 - 18	4.500	4.530	4.470	1.750	1.780	1.720	2.060	1.940	1 1/4
05	027	5/16 - 18	2.688	2.718	2.658	1.750	1.780	1.720	1.060	0.940	1 1/2
05	047	5/16 - 18	4.750	4.780	4.720	1.750	1.780	1.720	3.060	2.940	1 1/2
05	032	5/16 - 18	3.188	3.218	3.158	1.750	2.030	1.720	1.060	0.940	2
05	056	5/16 - 18	5.625	5.685	5.565	2.000	2.030	1.970	3.060	2.940	2
05	037	5/16 - 18	3.688	3.718	3.658	2.000	2.030	1.970	1.060	0.940	2 1/2
06	022	3/8 - 16	2.250	2.280	2.220	2.000	2.030	1.970	1.310	1.190	1/2
06	023	3/8 - 16	2.250	2.280	2.220	2.000	2.030	1.970	1.310	1.190	3/4
06	025	3/8 - 16	2.500	2.530	2.470	2.500	2.530	2.470	1.310	1.190	1
06	027	3/8 - 16	2.750	2.780	2.720	2.500	2.530	2.470	1.185	1.065	1 1/4
06	026	3/8 - 16	2.625	2.655	2.595	2.500	2.530	2.470	1.310	1.190	1 1/2
06	031	3/8 - 16	3.125	3.155	3.095	3.000	3.030	2.970	1.310	1.190	2
06	036	3/8 - 16	3.625	3.655	3.595	3.000	3.030	2.970	1.310	1.190	2 1/2
06	066	3/8 - 16	6.625	6.685	6.565	3.000	3.030	2.970	3.060	2.940	2 1/2
06	041	3/8 - 16	4.125	4.155	4.095	3.000	3.030	2.970	1.310	1.190	3
06	055	3/8 - 16	5.500	5.560	5.440	3.500	3.530	3.470	2.310	2.190	3 1/2
08	045	1/2 - 13	4.500	4.530	4.470	3.500	3.530	3.470	1.685	1.565	2 1/2
08	050	1/2 - 13	5.000	5.060	4.940	3.500	3.530	3.470	1.560	1.440	3
08	085	1/2 - 13	8.500	8.590	8.410	4.000	4.030	3.970	3.060	2.940	3
08	055	1/2 - 13	5.500	5.560	5.440	4.000	4.030	3.970	1.560	1.440	3 1/2
08	060	1/2 - 13	6.000	6.060	5.940	4.500	4.530	4.470	1.560	1.440	4
08	072	1/2 - 13	7.250	7.310	7.190	5.625	5.685	5.565	2.060	1.940	5
08	084	1/2 - 13	8.375	8.465	8.285	6.750	6.810	6.690	2.060	1.940	6
08	104	1/2 - 13	10.375	10.465	10.285	8.750	8.840	8.930	2.060	1.940	8
12	138	3/4 - 10	13.813	13.933	13.693	10.875	10.965	11.055	4.060	3.940	10
14	161	7/8 - 9	16.063	16.183	15.943	12.875	12.995	12.755	4.310	4.190	12
14	173	7/8 - 9	17.313	17.433	17.193	14.125	14.245	14.005	4.310	4.190	14
14	193	7/8 - 9	19.313	19.193	19.193	16.125	16.245	16.005	4.310	4.190	16
16	217	1 - 8	21.688	21.568	21.568	18.125	18.245	18.005	4.810	4.690	18

Notes :

• UNC Threads are standards for low strength materials, but UNF threads are usually available on special order.
• Dimension C should be measured at point 1/2L from the threaded end.