Common Port Threads

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NPT – National Pipe Thread

Thread type: Tapered
Seal Type: Metal To Metal (Pipe sealant/tape required)
Measure Thread diameter on female thread and subtract ¼” to determine nominal thread size.
Thread side info:

Inch SizeDash SizeNominal
Thread Size		Male Thread
O.D. (in)		Female Thread
I.D. (in)
1/8021/8-2713/32 (.41)3/8 (.38)
1/4041/4-1817/32 (.54)1/2 (.49)
3/8063/8-1811/16 (.68)5/8 (.63)
1/2081/2-1427/32 (.84)25/32 (.77)
3/4123/4-141 1/16 (1.05)1 (.98)
1161 - 11 1/21 5/16 (1.32)1 1/4 (1.24)
1 1/4201 1/4 - 11 1/21 21/32 (1.66)1 19/32 (1.58)
1 1/2241 1/2 - 11 1/21 29/32 (1.90)1 13/16 (1.82)
2322 - 11 1/22 3/8 (2.38)2 5/16 (2.30)

SAE J1926/Male O-Ring Boss (MORB)/Straight Thread O-Ring (STOR)

Thread type: Straight Thread
Seal Type: O-ring seal on male boss/chamfer groove
Thread side info:

Inch SizeDash SizeNominal
Thread Size		Male Thread
O.D. (in)		Female Thread
I.D. (in)
1/8025/16-245/16 (.31)9/32 (.27)
3/16033/8-243/8 (.38)11/32 (.34)
1/4047/16-207/16 (.44)13/32 (.39)
5/16051/2-201/2 (.50)15/32 (.45)
3/8069/16-189/16 (.56)17/32 (.51)
1/2083/4-163/4 (.75)11/16 (.69)
5/8107/8-147/8 (.88)13/16 (.81)
3/4121 1/16 -121 1/16 (1.06)1 (.98)
7/8141 13/16 - 121 3/16 (1.19)1 1/8 (1.10)
1161 5/16 - 121 5/16 (1.31)1 1/4 (1.23)
1 1/4201 5/8 - 121 5/8 (1.63)1 9/16 (1.54)
1 1/2241 7/8 - 121 7/8 (1.88)1 13/16 (1.79)
2322 1/2 - 122 1/2 (2.50)2 7/16 (2.42)

BSPP – British Standard Pipe (Parallel)

Thread type: Straight Thread (Often expressed as “G” threads)
Seal Type: Bonded Washer/Seal
Thread side info:

Inch SizeDash SizeNominal
Thread Size		Male Thread
O.D. (in)		Female Thread
I.D. (in)
1/8021/8-283/8 (.38)11/32 (.35)
1/4041/4-1933/64 (.52)15/32 (.47)
3/8063/8-1921/32 (.65)19/32 (.60)
1/2081/2-1413/16 (.82)3/4 (.75)
5/8105/8-147/8 (.88)13/16 (.80)
3/4123/4-141 1/32 (1.04)31/32 (.97)
1161 - 11 1 5/16 (1.30)1 7/32 (1.22)
1 1/4201 1/4 - 111 21/32 (1.65)1 9/16 (1.56)
1 1/2241 1/2 - 111 7/8 (1.88)1 25/32 (1.79)
2322 - 112 11/32 (2.35)2 1/4 (2.26)

JIC J514 – 37 Degree

Thread type: Straight Thread
Seal Type: Metal to Metal on 37 degree cone face
Thread side info:

Inch SizeDash SizeNominal
Thread Size		Male Thread
O.D. (in)		Female Thread
I.D. (in)
1/8025/16-245/16 (.31)9/32 (.27)
3/16033/8-243/8 (.38)11/32 (.34)
1/4047/16-207/16 (.44)13/32 (.39)
5/16051/2-201/2 (.50)15/32 (.45)
3/8069/16-189/16 (.56)17/32 (.51)
1/2083/4-163/4 (.75)11/16 (.69)
5/8107/8-147/8 (.88)13/16 (.81)
3/4121 1/16 -121 1/16 (1.06)1 (.98)
7/8141 13/16 - 121 3/16 (1.19)1 1/8 (1.10)
1161 5/16 - 121 5/16 (1.31)1 1/4 (1.23)
1 1/4201 5/8 - 121 5/8 (1.63)1 9/16 (1.54)
1 1/2241 7/8 - 121 7/8 (1.88)1 13/16 (1.79)
2322 1/2 - 122 1/2 (2.50)2 7/16 (2.42)

O-Ring Face Seal (SAE J1453)

Thread type: Straight Thread
Seal Type: O-ring seal on machined face
Thread side info:

Inch SizeDash SizeNominal
Thread Size		Male Thread
O.D. (in)		Female Thread
I.D. (in)
1/4049/16-189/16 (.56)1/2 (.51)
3/80611/16-1611/16 (.69)5/8 (.63)
1/20813/16-1613/16 (.82)3/4 (.75)
5/8101-141 (1.00)15/16 (.93)
3/4121 3/16-121 3/16 (1.19)1 1/8 (1.11)
1161 7/16-121 7/16 (1.44)1 3/8 (1.36)
1 1/4201 11/16-121 11/16 (1.69)1 5/8 (1.61)
1 1/2242-122 (2.00)1 15/16 (1.92)