ASME B18.31.2 Tap End Studs

ASME B18.31.2 Tap End Studs

Dimensions for Tap End Studs to ASME B18.31.2 Standard

Nominal Size
Thread Diameter, D, Inch.
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
Bm = tap end thread length (full threads)
LT = overall length (nominal length)
S = Standoff (when installed) = LT - BM
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.