Tag: Pipe

Posted on

National Pipe Thread (NPT) Tap Drill Size

Below is the National Pipe Thread – NPT Tap Drill Size Chart.  It tells us what size hole must be drilled to begin tapping the tapered NPT thread.

Standard NPT Tap Drill Sizes
NPT Size
 Tap Drill Size (in.)
Decimal Equivalent (in.)
1/16 – 27
“C”
0.242
1/8 – 27
“Q”
0.332
1/4 – 18
7/16
0.438
3/8 – 18
9/16
0.562
1/2 – 14
45/64
0.703
3/4 – 14
29/32
0.906
1.0 – 11•1/2
1•9/64
1.141
1•1/4 – 11•1/2
1•31/64
1.484
1•1/2 – 11•1/2
1•23/32
1.719
2.0 – 11•1/2
2•3/16
2.188
2•1/2 – 8
2•39/64
2.609
3.0 – 8
3•15/64
3.234

Metric Tap Drill Sizes
Standard UNC Tap Drill Sizes
Standard UNF Tap Drill Sizes

Posted on

National Pipe Thread (NPT) Sizes / Dimensions

What is the outer diameter of a pipe thread?  Pipes are odd in that their size is based roughly on the inner diameter of the pipe.  So when you have a National Pipe Thead – NPT fitting, the thread size is actually much larger than the name implies.


Pipe thread sizes

Nominal
NPT Size		 Outer
Diameter
inch (mm)		 Threads
per inch		 Pitch
of Thread
inch (mm)
1/16“ 0.3125 in (7.94 mm) 27 0.03704 in (0.94082 mm)
⅛” 0.405 in (10.29 mm) 27 0.03704 in (0.94082 mm)
¼” 0.540 in (13.72 mm) 18 0.05556 in (1.41122 mm)
3/8″ 0.675 in (17.15 mm) 18 0.05556 in (1.41122 mm)
½” 0.840 in (21.34 mm) 14 0.07143 in (1.81432 mm)
¾” 1.050 in (26.67 mm) 14 0.07143 in (1.81432 mm)
1″ 1.315 in (33.40 mm) 11½ 0.08696 in (2.20878 mm)
1¼” 1.660 in (42.16 mm) 11½ 0.08696 in (2.20878 mm)
1½” 1.900 in (48.26 mm) 11½ 0.08696 in (2.20878 mm)
2″ 2.375 in (60.33 mm) 11½ 0.08696 in (2.20878 mm)
2½” 2.875 in (73.02 mm) 8 0.12500 in (3.175 mm)
3″ 3.500 in (88.90 mm) 8 0.12500 in (3.175 mm)
4″ 4.500 in (114.30 mm) 8 0.12500 in (3.175 mm)
5″ 5.563 in (141.30 mm) 8 0.12500 in (3.175 mm)
6″ 6.625 in (168.27 mm) 8 0.12500 in (3.175 mm)
10″ 10.750 in (273.05 mm) 8 0.12500 in (3.175 mm)
12″ 12.750 in (323.85 mm) 8 0.12500 in (3.175 mm)
14″ OD 14 in (355.60 mm) 8 0.12500 in (3.175 mm)
16″ OD 16 in (406.40 mm) 8 0.12500 in (3.175 mm)
18″ OD 18 in (457.20 mm) 8 0.12500 in (3.175 mm)
20″ OD 20 in (508.00 mm) 8 0.12500 in (3.175 mm)
24″ OD 24 in (609.60 mm) 8 0.12500 in (3.175 mm)
Definition of pipe thread acronyms
NPT National Pipe Thread
FPT Female Pipe Thread
MPT Male Pipe Thread
PTF SAE short taper pipe thread – dryseal
NPTF American National taper pipe thread for dryseal pressure-tight joints
NPSM American National straight pipe thread for mechanical joints
NPSI American National straight intermediate pipe thread
GHT Garden Hose Thread
NST Fire Hose Thread
BSPT British Standard taper pipe thread (metric dimensions)
Posted on

SCHEDULE 40 & 80 – NPS PIPE DIMENSIONS (PVC, CPVC, ABS)

It’s not necessarily the most frequently needed specification, but you might find yourself needing to know the pipe dimensions from time to time.  Things like ID, OD, wall thickness for a given NPT pipe size are not obvious without a table to reference.


Schedule 40 Pipe Dimensions

Nom. Pipe Size (in) O.D. Average I.D. Min. Wall Nom. Wt./Ft. Max. W.P. PSI
1/8″ 0.405 0.249 0.068 0.051 810
1/4″ 0.540 0.344 0.088 0.086 780
3/8″ 0.675 0.473 0.091 0.115 620
1/2″ 0.840 0.602 0.109 0.170 600
3/4″ 1.050 0.804 0.113 0.226 480
1″ 1.315 1.029 0.133 0.333 450
1-1/4″ 1.660 1.360 0.140 0.450 370
1-1/2″ 1.900 1.590 0.145 0.537 330
2″ 2.375 2.047 0.154 0.720 280
2-1/2″ 2.875 2.445 0.203 1.136 300
3″ 3.500 3.042 0.216 1.488 260
3-1/2″ 4.000 3.521 0.226 1.789 240
4″ 4.500 3.998 0.237 2.118 220
5″ 5.563 5.016 0.258 2.874 190
6″ 6.625 6.031 0.280 3.733 180
8″ 8.625 7.942 0.322 5.619 160
10″ 10.750 9.976 0.365 7.966 140
12″ 12.750 11.889 0.406 10.534 130
14″ 14.000 13.073 0.437 12.462 130
16″ 16.000 14.940 0.500 16.286 130
18″ 18.000 16.809 0.562 20.587 130
20″ 20.000 18.743 0.593 24.183 120
24″ 24.000 22.544 0.687 33.652 120

Schedule 80 Dimensions

Nom. Pipe Size (in) O.D. Average I.D. Min. Wall Nom. Wt./Ft. Max. W.P. PSI
1/8″ .405 .195 0.095 0.063 1230
1/4″ .540 .282 0.119 0.105 1130
3/8″ .675 .403 0.126 0.146 920
1/2″ .840 .526 0.147 0.213 850
3/4″ 1.050 .722 0.154 0.289 690
1″ 1.315 .936 0.179 0.424 630
1-1/4″ 1.660 1.255 0.191 0.586 520
1-1/2″ 1.900 1.476 0.200 0.711 470
2″ 2.375 1.913 0.218 0.984 400
2-1/2″ 2.875 2.290 0.276 1.500 420
3″ 3.500 2.864 0.300 2.010 370
3-1/2″ 4.000 3.326 0.318 2.452 350
4″ 4.500 3.786 0.337 2.938 320
5″ 5.563 4.768 0.375 4.078 290
6″ 6.625 5.709 0.432 5.610 280
8″ 8.625 7.565 0.500 8.522 250
10″ 10.750 9.493 0.593 12.635 230
12″ 12.750 11.294 0.687 17.384 230
14″ 14.000 12.410 0.750 20.852 220
16″ 16.000 14.213 0.843 26.810 220
18″ 18.000 16.014 0.937 33.544 220
20″ 20.000 17.814 1.031 41.047 220
24″ 24.000 21.418 1.218 58.233 210