How to Identify and Measure Fittings
Pipe size is an industry designation, not the actual size. View information about how to measure threaded and unthreaded pipe and pipe fittings.
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Low-Pressure Iron and Steel Threaded Pipe Fittings
Use these fittings for low-pressure applications in noncorrosive environments.
Adapters for tanks create an inlet or outlet connection on the surface of any tank, pressure vessel, or drum. Adapters with weld end allow for a permanent connection. Adapters with extension fit tightly into the hole, which keeps the fitting steady during welding.
NPTF (Dryseal) threads, NPSC (National Pipe Straight Coupling) threads, and NPSL (National Pipe Straight Locknut) threads are compatible with NPT threads.
For technical drawings and 3-D models, click on a part number.
- For Use With: Diesel Fuel, Gasoline, Oil, Water
- Specifications Met: ASTM A181, ASME B1.20.1
| Pipe Size  | For Hole Dia. | OD | Lg. | Material | Each | |
NPT Female × Weld | ||||||
|---|---|---|---|---|---|---|
| 1/8 | 15/16" | 1 5/16" | 3/8" | Carbon Steel | 00000000 | 00000 |
| 1/8 | 15/16" | 1 1/2" | 9/16" | Carbon Steel | 00000000 | 0000 |
| 1/4 | 15/16" | 1 5/16" | 3/8" | Carbon Steel | 00000000 | 0000 |
| 1/4 | 15/16" | 1 1/2" | 9/16" | Carbon Steel | 00000000 | 0000 |
| 3/8 | 15/16" | 1 5/16" | 3/8" | Carbon Steel | 00000000 | 0000 |
| 3/8 | 15/16" | 1 1/2" | 9/16" | Carbon Steel | 00000000 | 0000 |
| 1/2 | 1 1/8" | 1 5/8" | 7/16" | Carbon Steel | 00000000 | 0000 |
| 1/2 | 1 1/8" | 1 3/4" | 5/8" | Carbon Steel | 00000000 | 0000 |
| 3/4 | 1 5/16" | 1 15/16" | 1/2" | Carbon Steel | 00000000 | 0000 |
| 3/4 | 1 3/8" | 2 1/8" | 11/16" | Carbon Steel | 00000000 | 0000 |
| 1 | 1 5/8" | 2 3/8" | 3/4" | Carbon Steel | 00000000 | 0000 |
| 1 | 1 11/16" | 2 1/4" | 9/16" | Carbon Steel | 00000000 | 0000 |
| 1 1/4 | 2" | 2 9/16" | 9/16" | Carbon Steel | 00000000 | 00000 |
| 1 1/4 | 2" | 2 11/16" | 3/4" | Carbon Steel | 00000000 | 0000 |
| 1 1/2 | 2 1/4" | 2 13/16" | 9/16" | Carbon Steel | 00000000 | 0000 |
| 1 1/2 | 2 1/4" | 3" | 3/4" | Carbon Steel | 00000000 | 0000 |
| 2 | 2 5/8" | 3 3/8" | 5/8" | Carbon Steel | 00000000 | 0000 |
| 2 | 2 5/8" | 3 1/2" | 27/32" | Carbon Steel | 00000000 | 00000 |
| 2 1/2 | 3 1/8" | 4 1/16" | 1" | Carbon Steel | 00000000 | 00000 |
| 3 | 3 5/8" | 4 5/8" | 1" | Carbon Steel | 00000000 | 00000 |
| 4 | 4 11/16" | 5 13/16" | 1 7/32" | Carbon Steel | 00000000 | 00000 |
- For Use With: Diesel Fuel, Gasoline, Oil, Water
- Specifications Met: ASTM A105, ASTM A181
| Pipe Size | For Hole Dia. | OD | Lg. | Material | Each | |
NPT Female × Weld | ||||||
|---|---|---|---|---|---|---|
| 1/4 | 3/4" | 1 1/4" | 5/16" | Carbon Steel | 00000000 | 00000 |
| 3/8 | 15/16" | 1 1/4" | 3/8" | Carbon Steel | 00000000 | 00000 |
| 1/2 | 1 1/8" | 1 1/2" | 1/2" | Carbon Steel | 00000000 | 0000 |
| 3/4 | 1 3/8" | 1 3/4" | 5/8" | Carbon Steel | 00000000 | 0000 |
| 1 | 1 11/16" | 2 1/8" | 5/8" | Carbon Steel | 00000000 | 0000 |
| 1 1/4 | 2" | 2 1/2" | 3/4" | Carbon Steel | 00000000 | 0000 |
| 1 1/2 | 2 3/8" | 3" | 3/4" | Carbon Steel | 00000000 | 00000 |
| 2 | 2 7/8" | 3 1/2" | 13/16" | Carbon Steel | 00000000 | 00000 |
| 2 1/2 | 3 1/2" | 4 1/4" | 1" | Carbon Steel | 00000000 | 00000 |
| 3 | 4 1/8" | 4 3/4" | 1" | Carbon Steel | 00000000 | 00000 |
| 4 | 5 1/8" | 5 3/4" | 1 3/16" | Carbon Steel | 00000000 | 00000 |
- For Use With: Diesel Fuel, Gasoline, Oil, Water
- Pipe Nipples and Pipe: Use Schedule 40 steel
Low-Pressure Stainless Steel Threaded Pipe Fittings
Use these fittings in a low-pressure pipe line. 316 stainless steel fittings have excellent corrosion resistance. Adapters with weld end allow for a permanent connection.
Adapters for tanks create an inlet or outlet connection on the surface of any tank, pressure vessel, or drum. Adapters with extension fit tightly into the hole, which keeps the fitting steady during welding.
NPTF (Dryseal) threads and NPSL (National Pipe Straight Locknut) threads are compatible with NPT threads.
For technical drawings and 3-D models, click on a part number.
- For Use With: Water, Oil, Gasoline, Diesel Fuel
- Specifications Met: ASTM A182, ASME B1.20.1
316 Stainless Steel | |||||
|---|---|---|---|---|---|
| Pipe Size | For Hole Dia. | OD | Lg. | Each | |
NPT Female × Weld | |||||
| 1/4 | 15/16" | 1 1/2" | 5/16" | 0000000 | 000000 |
| 3/8 | 15/16" | 1 1/2" | 5/16" | 0000000 | 00000 |
| 1/2 | 1 1/8" | 1 3/4" | 3/8" | 0000000 | 00000 |
| 3/4 | 1 3/8" | 2 1/8" | 7/16" | 0000000 | 00000 |
| 1 | 1 5/8" | 2 3/8" | 1/2" | 0000000 | 00000 |
| 1 1/4 | 2" | 2 11/16" | 1/2" | 0000000 | 00000 |
| 1 1/2 | 2 1/4" | 3" | 1/2" | 0000000 | 00000 |
| 2 | 2 5/8" | 3 1/2" | 9/16" | 0000000 | 00000 |
| 2 1/2 | 3 1/8" | 4 1/16" | 13/16" | 0000000 | 000000 |
| 3 | 3 5/8" | 4 5/8" | 13/16" | 0000000 | 000000 |
| 4 | 4 7/8" | 5 3/4" | 1 3/16" | 0000000 | 000000 |
Low-Pressure Aluminum Threaded Pipe Fittings
In addition to being lightweight, these aluminum fittings offer good corrosion resistance. Use them in low-pressure flow applications. To prevent cracking, do not tighten more than a 1/4-turn past hand tight.
Adapters for tanks weld onto the surface of any tank, pressure vessel, or drum to create a permanent inlet or outlet connection. Adapters with extended lip fit tightly into the hole, which keeps the fitting steady during welding.
NPTF (Dryseal) threads and NPSL (National Pipe Straight Locknut) threads are compatible with NPT threads.
For technical drawings and 3-D models, click on a part number.
- For Use With: Water, Oil, Gasoline, Diesel Fuel
- Specifications Met: ASTM B221
- Pipe Nipples and Pipe: Use Schedule 40 aluminum
| Pipe Size | For Hole Dia. | OD | Lg. | Each | |
NPT Female × Weld | |||||
|---|---|---|---|---|---|
| 1/8 | 7/8" | 1 5/16" | 1/4" | 0000000 | 00000 |
| 1/4 | 7/8" | 1 5/16" | 1/4" | 0000000 | 00000 |
| 3/8 | 1 3/16" | 1 7/16" | 1/4" | 0000000 | 00000 |
| 1/2 | 1 1/8" | 1 5/8" | 1/4" | 0000000 | 00000 |
| 3/4 | 1 5/16" | 2" | 1/4" | 0000000 | 00000 |
| 1 | 1 11/16" | 2 1/4" | 1/4" | 0000000 | 00000 |
| 1 1/4 | 1 15/16" | 2 9/16" | 5/16" | 0000000 | 00000 |
| 1 1/2 | 2 1/4" | 2 15/16" | 5/16" | 0000000 | 00000 |
| 2 | 2 5/8" | 3 3/8" | 5/16" | 0000000 | 00000 |
| 3 | 3 11/16" | 4 5/8" | 3/4" | 0000000 | 000000 |
| 4 | 4 3/4" | 5 13/16" | 7/8" | 0000000 | 000000 |
Spin-Weld Through-Wall Plastic Tank Fittings
Create a leak-free, durable connection in plastic tanks, walls, or panels without gaskets or sealants. As you spin these fittings with a handheld electric router, they melt into the surface of your tank for a seal without any joints. To hold these fittings in your router, you’ll need the installation tool (sold separately).
For proper installation, you’ll want to use a hole saw to drill a hole that matches the For Hole Diameter listed and check that your router meets the speed and power requirements shown in the table.
For technical drawings and 3-D models, click on a part number.
- For Use With: Oil, Water
- Temperature Range: 40° to 140° F
For Tank | For Router | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Pipe Size | For Hole Dia. | For Min. Wall Thick. | Lg. | Material | Material | Surface | Color | Power | Speed, rpm | Each | |
NPT Female Threaded Pipe × Weld | |||||||||||
| 1/4 | 0.88" | 3/16" | 15/16" | LDPE Plastic | LDPE Plastic | Flat | White | 1 1/2 | 18,000-25,000 | 0000000 | 00000 |
| 1/2 | 0.88" | 3/16" | 7/8" | LDPE Plastic | LDPE Plastic | Flat | White | 1 1/2 | 18,000-25,000 | 0000000 | 0000 |
| 3/4 | 1.31" | 3/16" | 13/16" | LDPE Plastic | LDPE Plastic | Flat | White | 1 1/2 | 18,000-25,000 | 0000000 | 0000 |
| 1 | 1.5" | 3/16" | 1" | LDPE Plastic | LDPE Plastic | Flat | White | 1 1/2 | 18,000-25,000 | 0000000 | 0000 |
| 1 1/2 | 2" | 3/16" | 1 3/16" | LDPE Plastic | LDPE Plastic | Flat | White | 1 1/2 | 18,000-25,000 | 0000000 | 0000 |
| 2 | 2.5" | 3/16" | 1 3/16" | LDPE Plastic | LDPE Plastic | Flat | White | 1 1/2 | 18,000-25,000 | 0000000 | 0000 |
| For Pipe Size | Shank Dia. | Overall Lg. | Material | Shank Type | For Tool Type | Each | |
For Pipe Connection | |||||||
|---|---|---|---|---|---|---|---|
| 1/4 | 1/4" | 1 5/8" | Aluminum | Straight | Hand Router | 000000 | 0000000 |
| 1/2 | 1/4" | 1 5/8" | Aluminum | Straight | Hand Router | 000000 | 000000 |
| 3/4 | 1/2" | 2" | Aluminum | Straight | Hand Router | 000000 | 000000 |
| 1 | 1/2" | 2 1/4" | Aluminum | Straight | Hand Router | 000000 | 000000 |
| 1 1/2 | 1/2" | 2 1/4" | Aluminum | Straight | Hand Router | 000000 | 000000 |
| 2 | 1/2" | 2 1/4" | Aluminum | Straight | Hand Router | 000000 | 000000 |