Dimensions of Tap End Studs to ASME B18.31.2 Standard

Nominal Size Diameter, D	Tap End Full Thread Length, BM			Umax = 2P			Minimum Nut End Full Thread Length, Bmin
	Nominal	Min.	Max.	UNC & NC-5 Thread	UNF Thread	8UN Thread	L ≤ 10	10 < L ≤ 16	L > 16
1/4	0.375	0.350	0.400	0.100	0.071	...	0.750	1.000	1.500
5/16	0.469	0.440	0.498	0.111	0.083	--	0.875	1.125	1.625
3/8	0.563	0.532	0.594	0.125	0.083	--	1.000	1.250	1.750
7/16	0.656	0.620	0.692	0.143	0.100	--	1.125	1.375	1.875
1/2	0.750	0.708	0.792	0.154	0.100	--	1.250	1.500	2.000
9/16	0.844	0.802	0.896	0.167	0.111	--	1.375	1.625	2.125
5/8	0.938	0.892	0.983	0.182	0.111	--	1.500	1.750	2.250
3/4	1.1.25	1.075	1.175	0.200	0.125	--	1.750	2.000	2.500
7/8	1.313	1.258	1.368	0.222	0.143	--	2.000	2.250	2.750
1	1.500	1.438	1.562	0.250	0.167	--	2.250	2.500	3.000
1 1/8	1.688	1.625	1.750	0.286	0.167	0.250	2.500	2.750	3.250
1 1/4	1.875	1.813	1.938	0.286	0.167	0.250	2.750	3.000	3.500
1 3/8	2.063	2.000	2.125	0.333	0.167	0.250	3.000	3.250	3.750
1 1/2	2.250	2.188	2.313	0.333	0.167	0.250	3.250	3.500	4.000
1 5/8	2.438	2.375	2.500	--	--	0.250	3.500	3.750	4.250
1 3/4	2.625	2.563	2.688	0.400	--	0.250	3.750	4.000	4.500
1 7/8	2.813	2.750	2.875	--	--	0.250	4.000	4.250	4.750
2	3.000	2.925	3.075	0.444	--	0.250	4.250	4.500	5.000
2 1/4	3.375	3.300	3.450	0.444	--	0.250	4.750	5.000	5.500
2 1/2	3.750	3.675	3.825	0.500	--	0.250	5.250	5.500	6.000
2 3/4	4.125	4.050	4.200	0.500	--	0.250	5.750	6.000	6.500
3	4.500	4.425	4.575	0.500	--	0.250	--	6.500	7.000
3 1/4	4.875	4.775	4.975	0.500	--	0.250	--	7.000	7.500
3 1/2	5.250	5.150	5.350	0.500	--	0.250	--	7.500	8.000
3 3/4	5.625	5.525	5.725	0.500	--	0.250	--	8.000	8.500
4	6.000	5.900	6.100	0.500	--	0.250	--	8.500	9.000

General Notes :
B = full nut end thread length
B_m = tap end thread length (full threads)
L_T = overall length (nominal length)
S = Standoff (when installed) = L_T - B_M
U = length to first full form thread.

Notes :

• UNC Threads are standards for low strength materials, but UNF threads are usually available on special order.