NPTLOK, Your Trustable Metric Pipe Nipples Manufacturer
ISO Metric Threads for European & Asian Markets
- We supply ISO metric parallel threads in sizes M10 to M30+.
- Available in SS304 and SS316, full material traceability
- Available in Hex, reducing, close, and long nipple types
- These pipe nipples can also be configured to any length you need from close nipples up to 12″.
NPTLOK Can Meet All Your Specific Metric Pipe Nipple Requirements
Our metric pipe nipples are precision-machined threaded fittings with ISO metric parallel threads (M series), designed for European and Asian markets where metric thread standards are required.
| Available Materials | SS304, SS304L, SS316, SS316L |
| Gewindestandard | ISO metric parallel threads (M series)
NOT compatible with NPT or BSP |
| Thread Sizes | M10, M12, M14, M16, M18, M20, M22, M24, M27, M30+ |
| Nipple Types | Hex nipple, reducing nipple, close nipple, long nipple, male-female nipple |
| Length Options | Close nipple, standard lengths (1″ to 12″), custom lengths |
| Surface Finish | Mill finish or passivated |
Important：Metric threads are NOT interchangeable with NPT or BSP threads. Please verify your thread standard before ordering.
Why Choose NPTLOK Metric Pipe Nipples
Why Choose NPTLOK Metric Pipe Nipples
- We specialize in the design of metric threads with particular emphasis on the ISO metric parallel threads. These thread designs are used extensively by companies in the European and Asian market-place.
- All of our metric pipe nipples are made in-house. We can give closer inspection and get better prices to ship out faster to our customers.
- Full Material Traceability: Every batch is with a material test certificate for the respective alloy. This material test certificate contains the heat number, the chemical composition and the mechanical properties.
- There are a number of nipple styles, including hex, reducing, close and long. All of our nipples come in a number of sizes in metric thread.
- Complete Size Range: All threads are available in metric from M10 to M30+ and in all lengths from the close nipple size to 12″ (or more) of whatever the custom length may be.
- We are able to scale down our MOQ for the first order if required. So if you require a small first order, we can start from as low as 10 pieces. This allows you to receive a small sample of product before placing a larger order.
Hexagonal center section that lets you install it with a standard metric wrench. Good for applications where you need to take things apart often or work in tight spaces. Available from M10 to M64, in SS304 or SS316.
Different thread sizes on each end :one side larger, one side smaller. For example, M20 to M16, or M24 to M20. Use it when you need to connect two ports of different sizes. Saves you from using an extra adapter and removes one potential leak point.
Very short :the threads run almost the entire length. Use it when you need to connect two fittings with very little space between them, or when a standard-length nipple just won’t fit. About as short as you can get.
Extended length for bridging gaps between connection points. Standard lengths from 1″ to 12″, or we can cut to whatever you need.
Male thread on one end, female thread on the other. For those times when you have a male port on one side and a female port on the other, and you just need a short piece to connect them.
The standard type: male threads on both ends. If you don’t need anything special, this is probably what you’re looking for. Metric threads from M10 to M64, made to your specified length.
Applications of NPTLOK Metric Pipe Nipples
Used on press machines. M20 and M22 metric nipples connect pumps to valve blocks. No thread conversion needed, just screw them in.
Pneumatic control panels on bottling lines use M16 metric nipples to link filter regulators with solenoid valves. Standard size over there.
SS316 metric nipples handle the salt spray and chemicals. Connect injection pumps to the distribution lines on offshore platforms.
Metric close nipples go between sanitary valves on stainless steel piping. Short length means less space for bacteria to hide during cleaning.
When to Choose Metric Pipe Nipples
There are several scenarios that you should choose metric pipe nipples:
- Equipment uses metric threads: Equipment manufactured in Europe, China, Japan, and South Korea typically uses metric threads.
- Export to metric-system countries: Projects in countries such as Germany, France, China, and Japan require metric standards.
- OEM supply for European customers: European OEM manufacturers require metric threaded components.
- The existing system is metric: if you have to maintain or expand a metric threaded system.
How to Identify Thread Standards (before You Order the Wrong One)
Ordering the wrong thread standard is a common and costly mistake. A metric nipple will not seal on an NPT port, it might go in a turn or two, then either leak or get stuck and damage both threads. You won’t know until you try to install it, and by then, the project is delayed and you have to order replacements.
If you are unsure which thread you need, you can:
- Measure the thread outer diameter:
Metric threads: Whole millimeters (e.g., 20 mm = M20)
NPT: Fractional inches (e.g., 0.84“ = 1/2” NPT)
- Check the thread profile:
Metric: 60° thread angle, parallel
BSP: 55° thread angle, parallel or tapered
NPT: 60° thread angle, tapered
- Check existing markings:
Metric: M20×1.5
NPT: 1/2-14 NPT
BSP: G1/2 or R1/2
Installation Guide
How to Seal Metric Threads (And What Happens If You Do It Wrong)
Metric threads are parallel, not tapered like NPT. This means they do not seal by themselves. If you treat them like NPT: wrap on some Teflon tape and screw it in, you will get one of two results: a slow leak you cannot stop, or a cracked port because you kept tightening trying to seal it.
Here is how to do it correctly, and which method works for your situation.
| Dichtungsverfahren | Description | Applications |
| O-Ring | Sealing O-ring groove at the thread root; O-ring compresses to form a seal | Most common
suitable for low- and medium-pressure applications |
| Gasket Sealing | Uses copper or PTFE gaskets | High-temperature or high-pressure applications |
| Sealant | Apply pipe thread sealant | Auxiliary sealing; cannot be used alone |
Quick Decision Guide
| Your situation | Use this |
| Normal hydraulic or pneumatic system, room temperature to 150°C | O-ring seal |
| Port has a flat face with no O-ring groove | Gasket seal |
| High temperature (steam, hot oil) | Gasket seal |
| High pressure (above 5000 psi) | Gasket seal |
| Someone told you “just use Teflon tape” | They are wrong. Use an O-ring or gasket. |
If you are not sure which one is fit for your situation, feel free to contact us to get further support.
Installation Steps of Metric Pipe Nipples
- Cleaning: Remove debris and oil from the port and threads
- Inspect O-ring/Gasket: Ensure the seal is intact
- Tighten it by hand first, so the threads line up properly. This is an important step to make sure everything fits together correctly.
- Tighten with a Wrench: Use an appropriate metric wrench to tighten to the recommended torque
- Make sure the seal is tight: Check that the O-ring or gasket is squeezed together properly.
Metric Thread Sizes and Applications
Threads are generally offered in a variety of sizes (measured in millimeters) and have various uses.
M10: Small instrumentation, pneumatic fittings
M12: General instrumentation
M14: Hydraulic ports, industrial equipment
M16: Common hydraulic port size
M18: Hydraulic systems
M20: Very common, hydraulic and pneumatic
M22: Large instrumentation
M24: Heavy industrial equipment
M27: Large hydraulic systems
M30+: Large-diameter piping
Need a size not listed? Let us know and we can customize for you!
Learn More about Us
- ISO-9001-Zertifikat
- MTC
- EAC1
- EAC2
- EAC3
- EAC4
- EAC5
No. Here’s why：
| Dimensions | Metric Thread | NVV | BSPT | BSPP |
| Thread Type | Parallel | Verjüngt | Verjüngt | Parallel |
| Thread Angle | 60° | 60° | 55° | 55° |
| Dichtungsverfahren | O-ring or gasket | Thread sealant | Thread sealant | O-ring or gasket |
| Primary Markets | Europe, Asia | North America | UK, Europe, Asia | UK, Europe, Asia |
Attempting to connect a metric thread to an NPT or BSP port will result in leaks, thread damage, or both.
It’s just a short piece of pipe with metric threads on both ends. You use it to connect two things that have metric ports like a valve and a fitting, or a pump and a pipe.
From M10 up to M30+. The common ones people order are M12, M16, M20, and M24. If you need something in between, just ask.
Normally 10 pcs.
