Jun, 2023

How to Seal Hydraulic Fittings

How to Seal Hydraulic Fittings?

It is critical for hydraulic systems and for operators to seal hydraulic fittings properly. This is because if a fitting is incorrectly sealed, it may cause damage to the fitting, system failure, and even injury to personnel.

Introduction

Hydraulic systems are an integral part of all types of industrial machinery and hydraulic equipment. They can only function properly if they are properly sealed. Proper sealing ensures that hydraulic fluid remains in the system, maintains system pressure, and prevents failures or leaks from occurring. Moreover, proper sealing is what prevents external contamination from affecting the operation of the hydraulic system.

To properly install hydraulic fittings, you need to understand how to seal hydraulic fittings.

Why fittings leak

Typically, hydraulic fittings leak due to incorrect installation, excessive pressure, thread damage, vibration, material incompatibility, and seal damage. All of these reasons may lead to leaking fittings, then cause damage to the hydraulic system and have an impact on your machinery, time, and economy. In this article, Topa will focus on how fittings are sealed and how to seal them to prevent leaks properly, please continue to read!

Sealing Methods

Although the specific structure of the various sealing forms is different, the sealing principle is that the metal surface or seals (such as O-rings, ED seals, gaskets, combination gaskets, etc.) and the metal surface between the seals are squeezed to form a sealing surface to stop the hydraulic oil from spilling.

Flat Face Seal

Flat face seals are classified as E-type port end seals, A-type port end seals, and O-ring face seals.

E-type port end seal

The E-type port end sea is a metric fine thread with an annular groove structure. The metric fine threads have good self-locking properties and are highly resistant to vibration and loosening. The groove structure requires the installation of packing seals, which can be made of fluoroelastomer or nitrile rubber. This method ensures that the straight threaded fitting forms a seal and reduces the risk of leakage.

A-type port end seal

Type A port end seal has a metric fine thread or a British standard pipe taper(BSPT)thread on the male end and requires a gasket or a combination gasket. The BSPT threads are tapered, similar to NPT threads, but they have different pitches, so there is a slight difference in the sealing method.

O-ring face seal

The O-ring face seal(ORFS)has a groove at the top of the fitting thread end that allows the O-ring to be installed. When the fittings are tightened, the O-ring and the top of the other fitting will fit together tightly to form a seal and prevent leakage.

Tapered Face Seals

Tapered seals are divided into flare-type seals, 24° tapered seals, 30° tapered seals, and compression seals.

24° internal chamfer	DIN/Metric
30° internal chamfer	BSPP	NPTF/NPSM
30° external flare	Komastu	JIS
37° external flare	JIC	Metric/GB
45° external flare	SAE 45°	AN 45°
Flat	ORFS/ORB	Metric	BSPT

Hydraulic fitting chart

Flared face seal

Flare face is also called chamfer or flare. The raised tapered face of the male thread is the flare seat, and the recessed face of the female thread is the inverted flare. When female and male threads are used together, the contact surfaces of the two will fit tightly, creating a hard metal-to-metal seal. Hydraulic fittings commonly have 37° tapered cone faces and 45° tapered faces, and the internal and external threads of these fittings can be installed to form a flared face seal.

24° tapered seal

The 24° taper seal is a composite seal. It is a combination of a metal-to-metal hard seal and a metal face with an O-ring elastic seal. The fitting end is a metric fine thread with a 24° flare (seal bevel angle). This sealing structure is the German standard and is suitable for components with strict requirements for pressure-resistance capacity and sealing capability. This tarped seal can withstand different levels of pressure. Depending on the pressure-resistance capacity, these fittings are classified as light or heavy-duty.

30° cone seal

The 30° tapered seal has a metric fine thread or British pipe thread with a groove on the male end and a metric fine thread with a 30° taper on the female end, which requires an O-ring. This sealing structure is mostly used for the connection between the valve body and connector, and the hydraulic system pressure measuring port.

Compression seal

The external thread of the compression seal is a 24° female taper and the internal thread is also a 24° male taper, and the two are clamped to each other by means of a ferrule. There are also one-piece and two-piece ferrule fittings, with one and two ferrules respectively. This structure is the same as the 24° cone (compound seal) internal cone, and the two internal cone fittings can be used interchangeably.

Other Sealing Methods

Teflon Tape

Teflon tape is made of Polytetrafluoroethylene film and is commonly white. This tape is wrapped clockwise around the male threads of the hydraulic fitting and then installed together with the female threads. However, Teflon tape is only suitable for some hydraulic systems. If Teflon tape is used in the wrong place, it is hard to form a seal and may even cause pieces of tape to contaminate the hydraulic fluid.

Thread Sealants

Liquid sealants can be applied to the metal surface of the fitting to fill in scratches. And defects on the fitting surface, preventing displacement and leakage. Thread sealants can be used on all-metal fittings to improve the sealability of the fitting.

Sealants are not normally supplied with metal fittings, except for DOT air brake fittings, so you should ask the manufacturer in advance before using a sealant.

How to Seal Hydraulic Fittings

All fittings only need to be installed correctly following the steps to ensure a seal.

First, clean the fitting surface

It would help if you made sure that the fitting surface and the installation area are clean and that there are no contaminants affecting the sealing effect.

Second, inspect the fitting

You need to check the fitting for damage. Then replace it with a new one immediately if there is any damage.

Then, choose the sealant

Generally, metal-to-metal sealed and O-ring sealed fittings do not require additional sealant. However, if you need to use sealant, choose the right sealant and use it with your fitting.

Next, install the fitting

When installing the fittings, either by hand or with the help of tools, make sure that the fittings are installed in place. But don’t install it too tightly, as this may cause the fitting to deform.

Finally, check carefully

The last step is also the most important one, you need to carefully check whether the installation is in place and whether it produces leaks. If you find any problems with the fitting seal, reinstall it again.

Conclusion

When selecting various sealing forms of fittings, be sure to consider the pressure, temperature, and compatibility of the environment in which they will be used. Regardless of the sealing form of the fitting, you must install the hydraulic fitting according to professional standards to ensure that the sealing will not fail and to ensure the safety of the hydraulic system.

FAQ

Which seal type works best?

Use O-rings (NBR/FKM material) for dynamic connections and Teflon tape/paste for tapered threads (NPT/BSPT). Match seal hardness (70-90 Shore A) to pressure.

How to prevent overtightening?

Follow torque specs (e.g., 1/2″ JIC = 85-100 Nm) – overtightening deforms sealing surfaces by 0.1mm can cause leaks.

Should I reuse seals?

Never reuse O-rings/seal washers – 95% of reinstallation leaks come from compromised seals.

How to seal parallel threads?

Use bonded seals (Dowty washers) or sealing collars for BSPP/SAE straight threads (ISO 8434-2 standard).

Why do flared fittings leak?

Clean 37° JIC/45° SAE flare surfaces with lint-free cloth – microscopic debris causes 60% of flare connection failures.

When to use thread locker?

Apply anaerobic sealant (Loctite 545) only on dry male threads for vibration-prone NPT/BSPT connections – avoid on flared/O-ring fittings.

Topa Blog

Find out more about Topa Blog and learn more about specialized hydraulic fittings.

Hydraulic Fitting Seal Forms: How to Differentiate?

NPT, PT, PF, G, ZG Threads, Can You Tell The Difference?

Hydraulic Hose Problems Unveiled: How to Prevent Them?

Types of Ball Valve Handles: Which One to Choose?

How to Measure Ball Valve Size: A Quick & Easy Guide

Ball Valve Standard Specification banner

Ball Valve Standard Specification: What You Need to Know

Jun, 2023

How to Measure Hydraulic Fittings

How to Measure Hydraulic Fittings?

Welcome to this all-inclusive guide on measuring hydraulic fittings, a crucial task that demands precision and expertise. Whether you’re a seasoned hydraulic salesperson or a maintenance professional, this guide is designed to walk you through the entire process. From selecting the right tools to understanding the significance of each measurement, we’ve got you covered. We’ll also shed light on common mistakes that can compromise your hydraulic system’s integrity. So let’s dive in and set the stage for a hydraulic system that’s both reliable and efficient.

Tools Required for Accurate Measurements

When it comes to measuring hydraulic fittings, you can’t afford to skimp on tools. The right tools not only make the job easier but also ensure that you get accurate and reliable measurements. Here’s what you’ll need:

Calipers or Measuring Tape

These are your go-to tools for measuring the diameter of the threads. Calipers are more precise, but a good-quality measuring tape can also do the job.

Thread Pitch Gauge

This tool is essential for determining the thread pitch, which is the distance between the threads. A wrong pitch can lead to incompatible fittings, so don’t overlook this.

Reference Charts

These charts contain standard sizes and dimensions for various types of hydraulic fittings. They’re a quick way to cross-reference your measurements.

Protractor

Protractors can be used to measure the angles of hydraulic fittings. The commonly fitting elbows are 30-degree, 45-degree, and 90-degree elbows, and there also exist other elbows. Special gauges are available to measure the angle of the sealing surface inside and outside of the fitting, such as 37-degree cone, 45-degree cone, and 30-degree cone.

Precautions to Take Before Measuring

Before you even touch a caliper or gauge, there are some precautions you need to take:

Depressurize the System: Always make sure the hydraulic system is off and depressurized. This is not just for your safety but also for accurate measurements.

Wear Safety Gear: Put on your gloves and safety glasses. It’s better to be safe than sorry.

Clean the Fitting: Dirt and debris can affect your measurements. Make sure the fitting is clean before you start.

Basic steps for measuring hydraulic fittings

Step 1: Determine the type of hydraulic fittings

First, you need to determine the types of hydraulic fittings. Is it a hose fitting or an adapter?

Before considering measurements, you need to determine the type of hydraulic fittings to be used. This step is critical because each fitting type has its own set of specifications and compatibility requirements. Whether you are an experienced hydraulic salesperson or a maintenance professional, knowing the type of fitting is the foundation for the work that follows.

There are several types of hydraulic fittings, each with its own set of standards. The most common types are JIC (Joint Industry Committee), NPT (National Pipe Thread), and ORFS (O-ring Face Seal). These are not just random acronyms, but industry standards that define the shape, thread, and function of the fitting.

So how do you recognize the type of fitting? First, check the fitting itself for any markings. Manufacturers usually print markings on the fitting type so that it is straightforward to identify. For example, in general, a US fitting will have two scores on it, whereas an imperial will only have one. If not, consult the manufacturer’s guide or specification sheet.

Why is this step so important? Using the wrong type of fitting can lead to a host of problems, from small leaks to catastrophic system failure. For example, NPT fittings may look similar to BSPT fittings, but they have different thread patterns and sealing methods. Mixing them up can be a recipe for disaster.

In short, determining the type of fitting is not only the first step, it’s a critical one. It sets the stage for all subsequent steps, from measurement to installation. So take your time, utilize the resources available, and make sure it’s correct. This is one area where you can’t rely on guesswork.

Step 2: Measuring thread diameter

Once the type of fitting has been determined, the next critical step is to measure the thread diameter. This may seem like a simple task, but it is both difficult and important. Thread diameter is a key factor in ensuring that hydraulic fittings are compatible with the rest of the system. Mismatched fittings can lead to leaks, inefficiency, and even system failure.

For this, you need a reliable measuring tool. Calipers are the most recommended standard tool in the industry, with accuracy to suit everyone’s needs. However, a high-quality tape measure can also do the job. Choosing between the two usually depends on the accuracy you need and the tools you have on hand.

For male threads, you need to measure the outside diameter. Place the caliper at the widest part of the thread, making sure it’s snug against the thread, but not so tight as to distort the thread. For female threads, the process is similar, but you are measuring the ID. Insert the caliper into the fitting and expand the caliper until it touches the inside wall.

Here’s a pro tip: Always double-check your measurements. Even the most experienced professionals can make mistakes, and in hydraulics, even a one-millimeter error can cause problems. Take several readings and then use the average value as the final measurement.

Why is this step so important? Because thread diameter directly affects a fitting’s ability to form a secure, leak-proof connection with the hose or component it connects to. Getting this wrong can jeopardize the integrity of the entire hydraulic system, not just a quick fix.

In short, measuring thread diameter should not be taken lightly. It requires precision, the right tools, and a double-checking mindset. Getting this right sets the stage for a reliable and efficient hydraulic system.

Step 3: Determining thread pitch

After measuring the thread diameter, the next critical step is to determine the thread pitch. Thread pitch is a critical factor in ensuring compatibility and a leak-free system. Thread pitch is essentially the distance between individual threads, measured in threads per inch (TPI). A mismatch in thread pitch can result in a poor fit, causing leaks and even damaged threads.

To measure thread pitch, you need a specialized tool called a thread pitch gauge. This tool comes with a variety of inserts, each labeled with a different TPI value. To use it, simply align the blades with the threads of the fitting until you find an exact match. This will give you the TPI value of the fitting.

Now, you may ask, what’s so important about this? Even if two fittings have the same diameter, differences in thread pitch can cause them to be incompatible. For example, a 14 TPI 1-inch NPT fitting will not fit a 12 TPI 1-inch NPT fitting. The threads won’t line up and you’ll either end up with a loose connection or damage the threads by forcing them together.

Here’s a pro tip: Always double-check the thread pitch measurement. A small mistake here can lead to big problems. If necessary, take several readings and confirm the TPI according to the manufacturer’s specifications whenever possible.

In hydraulics, it’s all in the details, and thread pitch is one detail that should not be overlooked. It’s not just about making sure you tighten the joint, it’s about ensuring a secure, long-lasting connection that won’t fail under pressure.

Step 4: Measuring seat angles

Once the thread diameter and pitch have been determined, it’s time to focus on another critical aspect: the seat angle. Seat angle is often overlooked, but it plays a critical role in ensuring a leak-proof connection. The angle is the inclination of the fitting seat as it interacts with its mating parts. Mismatched seat angles can lead to leaks, reduced system efficiency, and even component damage.

To measure the seat angle, you need to use a protractor or an angle-measuring tool designed for hydraulic fittings. Place the tool on the fitting seat and read the angle. The process is simple and straightforward but requires precision. One degree of deviation can compromise the integrity of your hydraulic system.

The seat angle determines how well the fitting seals against its mating parts. A perfect fit creates a leak-proof seal that can withstand high pressures and harsh conditions. Conversely, a mismatch can lead to leaks, which can be not only a nuisance but also a serious operational hazard. Leaks can lead to hydraulic fluid depletion, increased maintenance costs, and even, in extreme cases, system failure.

Here’s a pro tip: Always check seat angle measurements against the manufacturer’s specifications. This double-checking ensures that you are doing it correctly and helps you avoid costly mistakes.

In short, measuring the seat angle is a step that cannot be skipped or rushed through. It requires the right tools, consistent operation, and a meticulous attitude. Giving seat angle the attention it deserves not only ensures a leak-free connection but also improves the overall reliability and efficiency of your hydraulic system.

So the next time you choose a hydraulic fitting, don’t just focus on the threads. Give due attention to the valve seat angle as well. This small detail can have a major impact on the performance and reliability of your hydraulic system.

Step 5: Measuring fitting length

When it comes to hydraulic fittings, length is often the forgotten dimension. While thread diameter, pitch, and seat angle get all the attention, fitting length is just as critical to system performance and safety. Incorrect length can lead to improper sealing, increased stress on the fitting, and even system failure.

To measure fitting length, you’ll need a reliable measuring tool such as a caliper or straightedge. Align the tool with the joint, starting at one end and extending all the way to the other. Make sure you measure the entire length, including any flanges or extensions that may be part of the joint. You can’t use approximations for this step; accuracy is key.

Length directly affects a fitting’s ability to form a secure connection. Too short, and there’s a risk of an incomplete seal, leading to leaks. Too long, and it puts too much pressure on the joint and connecting parts, potentially leading to cracks or breaks over time.

Step 6. Cross-referencing measurement results

You’ve measured thread diameters, determined thread pitches, checked seating angles, and even verified joint lengths. But there’s one more critical step before you continue with the installation: cross-referencing the measurements. In this step, you take out your reference charts and double-check that each measurement meets industry standards and your specific needs.

Even small differences in measurements can lead to serious problems. Cross-referencing is the final quality check to ensure that the fittings you’re about to install are the correct fittings for your hydraulic system. It’s the last line of defense against leaks, inefficiencies, and potential system failures.

To cross-reference, compare your measurements to the data on a reference chart. These charts often include standard sizes, thread types, and dimensions for various hydraulic fittings. Make sure your fitting measurements match the types and sizes listed. If they don’t match, you’ll have to redesign.

Here’s a pro tip: Always have the latest reference charts on hand. Manufacturers occasionally revise specifications, and using outdated information can lead to errors.

In conclusion, cross-referencing measurements is not only a best practice but a necessity for anyone who values the reliability and safety of their hydraulic systems. It’s the final step in confirming that you’ve done your due diligence to ensure that the fittings you install today won’t cause problems tomorrow. Taking the time to cross-reference sets the stage for a durable hydraulic system.

Common Mistakes to Avoid

When it comes to hydraulic fittings, there is very little margin for error. Even seasoned professionals can make mistakes that compromise the integrity of the system. Here are some common mistakes to watch out for:

● Over-tightedning fittings

It’s a common misconception that the tighter you tighten, the better. Over-tightening hydraulic fittings can distort their shape, which can lead to leaks and even component failure. The key is to find a proper position so that the joint is firm but not stressed. Always use a torque wrench and follow the manufacturer’s torque specifications to avoid this mistake.

● Using incompatible thread types

In the world of hydraulics, not all threads are created equal. Using an incompatible thread type can definitely lead to failure. Always double-check that the threads of the fitting match the threads of the connected component. A mismatch can lead to leaks, inefficiency and even catastrophic failure.

● Improper use of sealing methods

Sealing is an art in itself. Using the wrong sealing method or material can compromise the integrity of your hydraulic system. Always follow the manufacturer’s instructions when using a sealing method. Whether it’s a thread sealant or an o-ring, using the correct sealing method is critical to a leak-proof connection.

Conclusion

By following these guidelines, you can ensure optimal performance and safety of your hydraulic system. If you only have old fittings and are not sure about the measured data, then you are welcome to contact us and we can give you an accurate answer！

FAQ

How to measure thread size?

Use a caliper to measure outer diameter (OD) of male threads or inner diameter (ID) of female threads in inches/mm, then match to SAE/ISO charts (e.g., 1″ OD = -16 dash size).

How to identify thread type?

Check thread angle and profile – NPT is 60° tapered, BSPP is 55° parallel, Metric is 60° flat crests. Use thread pitch gauges for verification.

How to measure fitting length?

Measure from sealing surface (flared face/O-ring groove) to the end of threads on straight fittings, excluding collars or nuts.

What is dash size?

A numbering system (-4, -8, -16) where dash size = 1/16″ increments (e.g., -8 = 8/16″ = 1/2″ tube OD).

How to measure port fittings?

For SAE ports: Measure major thread diameter; Count threads per inch (TPI); Confirm straight (ORFS) vs tapered (NPT)

How to verify seat angle?

Place 37° JIC or 45° SAE angle gauge against sealing surface – proper contact with no light gaps indicates correct angle.

Topa Blog

Find out more about Topa Blog and learn more about specialized hydraulic fittings.

Hydraulic Fitting Seal Forms: How to Differentiate?

NPT, PT, PF, G, ZG Threads, Can You Tell The Difference?

Hydraulic Hose Problems Unveiled: How to Prevent Them?

Types of Ball Valve Handles: Which One to Choose?

How to Measure Ball Valve Size: A Quick & Easy Guide

Ball Valve Standard Specification: What You Need to Know

May, 2023

What are hydraulic fittings?

What Are Hydraulic Fittings?

Currently, hydraulic systems exist in many applications, so it is vital to understand the knowledge of hydraulic fittings. Now you can follow us and learn more about hydraulic fittings!

Content

Introduction
Types of hydraulic fittings
Threads of hydraulic fittings
Common Materials of Hydraulic Fitting
International Standards
Applications
Select the correct fittings
Hydraulic fitting identification
Hydraulic fitting installation
The Production Process of Hydraulic Fittings
Hydraulic fitting sealing methods
Conclusion

Introduction

Hydraulic fittings are components that act as connections. They connect the components of a hydraulic system to form a strong seal and ensure the proper functioning of the hydraulic system. Hydraulic fittings allow the hydraulic fluid to combine or diver. In some hydraulic systems, special hydraulic fittings can change the direction of the fluid. Also, hydraulic fittings like plugs can be used as the end of a hydraulic piping system to stop fluid leaks.

Usually, hydraulic fittings are metal products that can withstand different pressure specifications. Common fittings vary in corrosion resistance, wear resistance, and sealing properties depending on the materials. Most fittings are made according to international standards, so they can be adapted to fit the needs of all applications.

All Types of Hydraulic Fittings

Hydraulic fitting is a collection. There are many sub-categories of hydraulic fittings, which differ in appearance, function, and operating conditions.

Hose fittings

One end of a hydraulic hose fitting is the threaded end and the other end is the hose connection end. The threaded end is divided into a male and a female end, the male end are external threads and can be connected with the female end. The hose end is inserted into the corresponding size of the hose and can be fixed with the help of clamps.

Adapters

Both ends of the adapter are threaded ports. The hydraulic adapter has male-to-male, male-to-female, and female-to-female types. Both sides of the adapter can be the same threads or different threads.

Tee and Cross

Tee fitting has three threaded ends and a cross fitting has four threaded ends. Tee and cross fittings are used to divide the fluid into different directions, tee fittings can divide the fluid into two directions and the crosses can divide the fluid into three directions.

Bulkhead

Bulkhead fittings are used to pass through a fixed wall or plate to connect the fitting to other components. They are usually used in bulkheads or tanks.

Reusable/Field attachable

A reusable (field-attachable) hydraulic fitting has a threaded end on one end, a hose end with a reusable sleeve on the other. These fittings are easy to disassemble and install. And can be removed or installed multiple times.

One-piece

One-piece fittings are different from reusable fittings because they are one-piece fittings with non-removable sleeves. These fittings are commonly available in the 43 series, 71 series, and HY series.

Plug and cap

A plug is a male threaded fitting and a cap is a female threaded fitting. They are both used at the end of a pipe system to stop fluid leakage or contamination.

Flange

Flange fittings can be used in high-pressure environments and are bolted together to form a seal. There are two main types of flange fittings: SAE Code 61 and Code 62 series.

Ferrule

The Ferrule is a cylindrical metal fitting used with hydraulic hoses to secure hoses and hose fittings.

Topa can offer different types of hydraulic hose fittings and hydraulic adapters, please contact us!

Hydraulic Fitting Thread Types

Every hydraulic fitting has threads, the most common threads used internationally are as follows:

Threads	Types
JIC(Joint Industrial Council)	Parallel
NPTF(National Pipe Tapered Fuel)	Tapered
NPSM(National Pipe Straight Mechanical)	Tapered
BSPP (British Standard Pipe Parallel)	Parallel
BSPT(British Standard Pipeapered)	Tapered
JIS(Japanese Industrial Standards)	Parallel
Metric/DIN	Tapered/Parallel

JIC

JIC (Joint Industrial Council) is a 37-degree or 74-degree cone flare thread, which is more popular in the U.S. JIC fittings threads are a form of metal-to-metal sealing and do not require additional sealant.

BSP

The BSP (British Standard Pipe)thread is more popular in the UK. It has two types, BSPP(Parallel), which is a straight thread, and BSPT(Tapered), which is a tapered thread. Both of these threads are 60-degree cones.

NPT

The common branches of NPT threads are NPSM(National Pipe Straight Mechanical) and NPTF(National Pipe Tapered Fuel). NPT has a certain taper to create a metal-to-metal seal.

JIS

JIS is the thread type that is used more often in East Asian countries such as Japan. This thread is a 30-degree cone, similar to the BSP thread, but not identical.

Metric/DIN

Metric threads are also known as DIN threads. The standard metric thread is the 24-degree cone and is available in both light and heavy-duty. They are popular all over the world.

ORFS

O-rings seal means fittings have O-rings in the flat grooves, and these fittings are highly resistant to sealing and vibration.

AN

The AN (Army-Navy) thread is a 37-degree flare, similar to the JIC thread, but not exactly the same as other flare threads.

Common Materials of Hydraulic Fittings

In the hydraulic environment, metal fittings are the most common choice. In hydraulic environments, metal hydraulic fittings are the most common.

Depending on the acid or alkaline environment and pressure range, the type of metal fitting varies.

The most common metal types used in hydraulic systems are carbon steel, stainless steel, brass, and aluminum.

Carbon Steel

The most common metal used in hydraulic systems is carbon steel. Carbon steel is made of carbon and steel and can be used in many applications. Carbon steel connectors are less resistant to corrosion but are easy to process, resistant to pressure, and cost-effective.

Stainless Steel

In some ways, stainless steel is the most superior metal. Stainless steel fittings are resistant to corrosion, pressure resistance, and abrasion resistance, durable and strong, but can be relatively expensive. Stainless steel fittings are available in many standards, with 304 and 316 being the most popular choices.

Brass

Brass consists of copper and zinc, which is a special alloy. Brass in general is highly resistant to corrosion and is highly machinable. Brass fittings and tubing are recommended for applications such as automotive, domestic, and industrial.

Aluminum

Aluminum fittings are moderately corrosion-resistant, lightweight, and suitable for low-pressure environments. Aluminum brake fittings are more commonly used in automobiles and aircraft.

International Standards

ISO: ISO (International Organization for Standardization) is a world-class standard that covers many aspects of hydraulic fitting testing. These standards specify the performance and dimensional requirements for hose fittings, flanges, quick fittings, etc.

SAE: SAE (Society of Automotive Engineers) specifies standards for hydraulic fittings and hydraulic hoses to ensure that these fittings are dimensionally correct and can withstand the appropriate operating pressures. The most common standards for fittings and hoses are SAEJ512, SAEJ516, and SAEJ514.

DIN: DIN (Deutsches Institut für Normung) is a German standard that defines the thread, dimensional, and operational requirements for hydraulic hose fittings, compression fittings, and adapters.

Some famous brands have developed their own standards, such as Parker, Gates, Eaton, etc. Topa can do all kinds of standards, please contact us and tell us your needs.

Applications

Hydraulic fittings can be applied in a wide range of applications. As long as there are hydraulic systems in the applications, there is a definite need for hydraulic fittings. Different sizes, materials, and types of fittings are used in different environments. In general, these areas will require the use of fittings:

Agriculture: Tractors, harvesters, and irrigation systems all need hydraulic adapters.

Industry: Hydraulic systems are present in most equipment in industrial applications, so hydraulic fittings are present to keep the system running properly.

Construction: Excavators, bulldozers, and other large machinery and equipment require high-quality hydraulic fittings.

Oil and gas: Transporting and storing oil and gas requires hydraulic fittings that do not create leaks.

Marine: Marine transportation or offshore oil wells require corrosion-resistant, strong-sealing hydraulic fittings.

Transportation: Many industries will need to transport materials, so hydraulic piping can ensure the safe transportation of fluids under pressure.

Automotive: There are specific standard fittings for brake systems and fuel systems in automobiles. These fittings ensure the proper operation of the system.

Topa can offer security service and transportation to all customers, so contact us!

Selecting The Correct Hydraulic Fittings

The hydraulic system can only maintain normal operation if the correct hydraulic fittings are selected. Therefore, the selection of the right hydraulic fittings should be considered from the following aspects:

Size

The right size corresponds to the right installation for the right application.For example, imperial sizes are 1/8′, 3/8′, and 1/2′. Metric sizes are M8*1.0, M10*1.0, and M22*1.5, etc. American sizes are 1/8, 1 1/4, and 2, etc. When selecting a fitting, choose the fitting size carefully.

Hydraulic fittings size chart

No.	02	04	05	06	08	10	12	16	20	24	32
BSPP	G1/8″×28	G1/4″×19		G3/8″×19	G1/2″×14	G5/8″×14	G3/4″×14	G1″×11	G1.1/4″×11	G1.1/2″×11	G2″×11
BSPT	R1/8″×28	R1/4″×19		R3/8″×19	R1/2″×14		R3/4″×14	R1″×11	R1.1/4″×11	R1.1/2″×11	R2″×11
NPT	Z1/8″×27	Z1/4″×18		Z3/8″×18	Z1/2″×14		Z3/4″×14	Z1″×11.5	Z1.1/4″×11.5	Z1.1/2″×11.5	Z2″×11.5
JIC		7/16″×20	1/2″×20	9/16″×18	3/4″×16	7/8″×14	1.1/16″×12	1.5/16″×12	1.5/8″×12	1.7/8″×12	2.1/2″×20
ORFS		9/16″×18		11/16″×16	13/16″×16	1″ ×14	1.3/16″×12	1.7/16″×12	1.11/16″×12	2″×12
SAE				5/8″×18			1.1/16″×14
Flange					1/2″	5/8″	3/4″	1″	1.1/4″	1.1/2″	2″
Push in		04		06	08		12	16	20	24	32
Note: Metric threads are marked according to the outside diameter of the thread, and tube straight pipe is marked according to the outside diameter of the straight pipe.

Temperature

In hydraulic systems, there are differences in ambient temperatures. And the operating temperature range of hydraulic fittings should be selected according to the ambient temperature.

Application

The application environment of a hydraulic fitting determines the type of fitting. There are detailed differences in the types of fittings used for agricultural, industrial, marine, transportation, and automotive applications.

Media

The media present in a hydraulic system can cause differences in pH, temperature, pressure, and friction, so the fitting should be compatible with the media to ensure no leaks or contamination.

Materials

Different environments will require different materials for hydraulic fittings. Also, the cost of the fittings differs from material to material.

Pressure

The rated pressure of the hydraulic fitting should be higher than the system pressure to ensure that the hydraulic system will not leak or be damaged.

Hydraulic Fittings Identification

Each hydraulic fitting has its own characteristics, but some of them are not very obvious, so how to distinguish them?

First, observe the shape.

If one end of the fitting is a tube and the other end is threaded, then this is a hose fitting; if both fitting ends are threaded, then it is a hydraulic adapter. A fitting with three ports is a tee, and one with four is a cross fitting; The body of the swivel fitting can be rotated in all directions, and the sleeve of the reusable fitting is removable, while the one-piece fitting is a whole part.

Next, use a thread gauge.

Some threads can be observed visually as straight or tapered threads. For example, BSPT and NPT are tapered threads. BSPP and UN/UNF are straight threads. If it is difficult to observe, use the corresponding thread gauge to check.

Then you can use a pitch gauge to measure the pitch.

Use vernier calipers to determine the size of the fitting, or the inside(I.D) and outside diameter (O.D)of the fitting.

If you really can’t identify what type of fitting you have, check your supplier’s data, or contact us directly!

Hydraulic Fittings Installations

Hydraulic fittings are divided into two major categories, hydraulic hose fittings, and hydraulic adapters. The two types of fittings differ in some details of the tools used and the installation process.

Selecting the right tool

Adjustable wrench: It can be adjusted according to the size of the fitting or hexagonal nut.

Cutting tool: used to cut the hose, tube, or pipe.

Sealant: Prepare sealing measures in advance if needed.

Protective equipment: Prepare gloves or goggles to protect yourself.

Installation

Hose fitting

Inspection: Check the appearance of the fitting before installation to make sure the threads are free of burrs, rust, and breakage.

Cutting: Cut the hose to the proper length.

Installation: Install the hose end of the fitting into the hose and tighten the nut to form a hose assembly. For crimp fittings, use a crimper to secure the fitting.

Test: Test for leaks in the hydraulic system.

Hydraulic adapter

Inspection: Check that there are no scratches, burrs, or breaks on the adapter.

Installation: You can apply a little lubrication to the adapter, use a wrench, and screw the fitting into the installation position. If the fitting has an O-ring seal, make sure the O-ring is not broken. And make sure the O-ring is installed in the correct position.

Testing: Test the assembly to make sure there are no leaks in the hydraulic system.

In addition, there are some special fittings: welded hydraulic fittings. These types of hydraulic fittings require professional installers to weld them.

If you have any installation questions, contact us!

The Production Process of Hydraulic Fittings

The factory will strictly follow each step of the process when producing hydraulic fittings to make the best quality fittings.

Raw material purchase – Raw material processing – CNC Lathe processing – Surface treatment – Inspection

Hydraulic fittings are generally processed using hot forging, which greatly improves the strength and toughness of the fittings.

In CNC lathe processing, the fitting will go through several steps, including punching, profile processing, and thread processing.

After the fitting is processed, it needs to undergo surface treatment to improve the aesthetics of the fitting. Common treatments include galvanizing, pickling, grinding, polishing, etc.

All fittings of Topa are inspected several times for appearance, threads, and quality. Topa factory uses salt spray testers, pulse testers, and other instruments for this purpose.

Hydraulic Fittings Sealing Methods

Some hydraulic fittings can be sealed directly by the metal surface, or by O-rings. Except for this type of fittings, others need some external help.

Teflon tape: can be wrapped directly around the threads to create a seal during installation; NPT threads often require tape to create seals.

Sealant: Loctite 5452 liquid thread sealant can be applied directly to the threads. When the fitting is used in a hydraulic system, it can directly seal the gap between the fitting and the component connection.

Conclusion

Hydraulic fittings are an integral component of the hydraulic system. Therefore, it is crucial for everyone to learn about all aspects of hydraulic fittings.

Topa is a professional hydraulic fitting factory and industry, we know a lot about hydraulic fitting products, if you still have questions, please contact us!

FAQ

How to choose the right hydraulic fitting?

Match thread type (SAE/JIC/Metric), pressure rating (exceed system needs by 25%), and material compatibility with your fluid and environment.

Why do hydraulic fittings leak?

Common causes include improper tightening, damaged seals, or contamination – always use manufacturer torque specs and inspect O-rings regularly.

Can I mix fittings from different brands?

Only if they meet the same industry standards (ISO/SAE) and have matching sealing geometries to ensure proper sealing.

How to prevent fitting corrosion?

Use corrosion-resistant materials like stainless steel or brass, and apply protective coatings for harsh environments.

What's the typical lifespan of hydraulic fittings?

Depending on material (stainless lasts longest) and application – replace if cracks/deformation appear.

How to identify fitting specifications?

Check markings for dash size (-08 = 1/2″), thread code (e.g., M16x1.5), and pressure class – cross-reference with manufacturer charts.

Topa Blog

Find out more about Topa Blog and learn more about specialized hydraulic fittings.

Hydraulic Fitting Seal Forms: How to Differentiate?

NPT, PT, PF, G, ZG Threads, Can You Tell The Difference?

Hydraulic Hose Problems Unveiled: How to Prevent Them?

Types of Ball Valve Handles: Which One to Choose?

How to Measure Ball Valve Size: A Quick & Easy Guide

Ball Valve Standard Specification: What You Need to Know

Air Conditioning Fitting Manufacturer

◆ Corrosion resistance

◆ Leak free

◆ High-quality

◆ Easy to operate

Compatible Air Conditioning Fitting Manufacturer in China

Air conditioning hose fittings are fittings used to connect air conditioning pipes and can be installed with only simple tools. Topa offers a wide range of high quality air conditioning pipe fittings. If you have any doubts about fittings, please contact me.

Product List

Topa can supply fittings for various types of air conditioning fittings. There are many types of air conditioning fittings, such as hose barb fittings, bulkhead fittings, flare fittings, compressor fittings, etc. If you don’t see the product you need below, please contact our staff.

Air Conditioning Fitting Video

The video below is about air conditioning pipe fittings, you can click to check the details. If you still have questions, you can contact us.

Topa Manufacturer Hydraulic Fittings

We are hydraulic fittings manufacturer, we provide all types of hydraulic fittings, so if you want to know more information, please feel free to contact us.

Your Reliable Air Conditioning Fitting Manufacturer

Air conditioning hose fittings are fittings used to connect air conditioning pipes and can be installed with only simple tools. Topa air conditioning pipe fittings are usually made of metal, the most common metals are brass, copper, steel and so on.

In addition, our air conditioner fittings also have many advantages:

Top-quality
Corrosion-resistance
Heat-resistance
Leak-free
Multiple application

Why Choose Us

Topa is a company that specializes in hydraulic fittings. We can supply fittings in various threads, sizes and materials, in addition to hydraulic hoses, cylinders, industrial hoses, ball valves, safety ropes, etc. These products are not only guaranteed quality, but they are also available at the right price.

Topa also has many advantages.

Work attitude

Our staff treats every customer with full enthusiasm and strict working attitude, and we will try our best to solve your problems and confusion.

Shipping Speed

After a successful product order, we will arrange production and shipping as soon as possible, and try our best to deliver the goods to customers as fast as possible.

Free samples

If we have stock, we can provide a small amount of samples.

4. Customized service

If your demand reaches a certain quantity, then we can provide customized products.

Application

Air conditioning hose fittings can be used in a wide range of applications, mainly in automotive air conditioning systems, heating systems, and various air conditioning systems.

Air Conditioning Fitting Quality Control

For each Topa product, multiple checks such as manufacturing monitoring, quality testing and packaging inspection are carried out to ensure the quality and level of the product.

hydraulic grease fitting China manufacturer check one by one

hydraulic grease fitting China supplier process Pulse test

hydraulic grease fitting factory process Three Coordinate Measuring

hydraulic grease fitting manufacturer Assemble in China

hydraulic grease fitting China manufacturer check size

hydraulic grease fitting China supplier quality check

FAQ

What is the air conditioning hose fitting?

Air conditioning hose fittings are fittings used to connect air conditioning pipes and can be installed with only simple tools.

What are the types of air conditioning fittings?

There are many types of air conditioning fittings, such as hose barb fittings, bulkhead fittings, flare fittings, compressor fittings, etc.

What are the materials of air conditioning fittings?

Air conditioning pipe fittings are usually made of metal, the most common metals are brass, copper, steel and so on.

What are the advantages of air conditioning hose fittings?

The advantages of air conditioning fittings are evident, they are easy to disassemble and install, corrosion resistant, high temperature resistant, not easily to wear, and have a long service life.

Where can air conditioning hose fittings be used?

Air conditioning crimp fittings can be used in a wide range of applications, mainly in automotive air conditioning systems, heating systems, and various air conditioning systems.

Can you use compression fittings on air conditioner?

Absolutely. Compression fittings make the installation and maintenance of air conditioning pipe much easier, they can withstand high pressures, the connections are very strong and easy to handle.

Can I request a sample before deciding to buy from you?

Yes, we can supply free samples if there are not too many, but generally the customer to pay the freight.

How will my order be shipped?

Normally it is shipped by sea, a small order or rush order can be shipped by air or courier after receiving your agreement.

Can I have my own customized product?

Yes, we can supply logo Print and package desiged based in our MOQ.

How long is your delivery time?

Generally it is 5-10 days if the goods are in stock. Or it is 25-35 days if the goods are not in stock, it is according to quantity.

Get More Information About Products

JIC to NPT hydraulic fitting

JIC to NPT Hydraulic Fitting

Topa can supply all types and sizes of JIC to NPT hydraulic fittings. JIC to NPT hydraulic fittings have different types and dimensions. If you have needs for JIC to NPT hydraulic fitting, please contact us for more information.

JIC to NPT Hydraulic Fitting Video

This video is about Topa JIC to NPT hydraulic fitting, it includes different types of Topa JIC to NPT hydraulic fittings.

If you need more information about our JIC hydraulic adapters, or if you would like to request free samples, please do not hesitate to contact us. Our expert team is always available to provide personalized assistance and answer any questions you may have.

Thank you for considering Topa for your hydraulic fitting needs. We are committed to delivering high-quality products and exceptional customer service to ensure your complete satisfaction.

JIC Hydraulic Fitting Catalog

Topa offers different types of JIC hydraulic fitting, this catalog includes all kinds of JIC hydraulic fittings.

If you have any questions about our JIC hydraulic fittings or need assistance in selecting the right sizes and types for your application, our expert team is here to help. We pride ourselves on offering exceptional customer service and technical support to ensure you have a seamless experience with Topa.

Male one-piece hydraulic fitting

Male One-piece Hydraulic Fitting

Topa can supply different types and sizes of male hydraulic one-piece fittings. All of those fittings are available in many kinds of materials, and can be used in lots of applications. And they can be compatible with Parker hydraulic fittings. If you have needs of hydraulic fittings, please contact us for more information.

Topa Male One-piece Hydraulic Fittings

This video is about topa male one-piece hydraulic fitting, it includes all the types of male hydraulic one-piece fitting. Topa can provide different sizes for our customs. If you have any questions about male hydraulic fitting, please contact us.

Male One-piece Hydraulic Fitting Catalog

Topa offers different types of male one-piece hydraulic fitting, this catalog includes all kinds of flange hydraulic fittings. If you need more information on male one-piece hydraulic fitting, please contact us.

Metric one-piece hydraulic fitting

Metric one-piece Hydraulic Fitting

Topa can supply different types and sizes of metric hydraulic one-piece fittings. All of those fittings are available in many kinds of materials and can used in lots of applications. If you have needs of hydraulic fittings, please contact us for more information.

Topa Metric One-piece Hydraulic Fittings

This video is about Metric one-piece hydraulic fitting, it includes all the types of Metric hydraulic one-piece fitting.Topa can provides different sizes for our customs.If you have questions, please contact us,we will try our best to save your problems.

Metric one-piece Hydraulic Fitting Catalog

Topa offers different types of Metric one-piece hydraulic fitting, this catalog includes all kinds of Metric hydraulic fittings. If you need more information of Metric one-piece hydraulic fitting, please contact us.

Jun, 2023

How to Seal Hydraulic Fittings?

Table of Contents

Introduction

Why fittings leak

Sealing Methods

Flat Face Seal

E-type port end seal

A-type port end seal

O-ring face seal

Tapered Face Seals

Flared face seal

24° tapered seal

30° cone seal

Compression seal

Other Sealing Methods

Teflon Tape

Thread Sealants

How to Seal Hydraulic Fittings

Conclusion

FAQ

Which seal type works best?

How to prevent overtightening?

Should I reuse seals?

How to seal parallel threads?

Why do flared fittings leak?

When to use thread locker?

Topa Blog

Jun, 2023

How to Measure Hydraulic Fittings?

Table of Contents

Tools Required for Accurate Measurements

Calipers or Measuring Tape

Thread Pitch Gauge

Reference Charts

Protractor

Precautions to Take Before Measuring

Basic steps for measuring hydraulic fittings

Step 1: Determine the type of hydraulic fittings

Step 2: Measuring thread diameter

Step 3: Determining thread pitch

Step 4: Measuring seat angles

Step 5: Measuring fitting length

Step 6. Cross-referencing measurement results

Common Mistakes to Avoid

● Over-tightedning fittings

● Using incompatible thread types

● Improper use of sealing methods

Conclusion

FAQ

How to measure thread size?

How to identify thread type?

How to measure fitting length?

What is dash size?

How to measure port fittings?

How to verify seat angle?

Topa Blog

May, 2023

What Are Hydraulic Fittings?

Content

Introduction

All Types of Hydraulic Fittings

Hydraulic Fitting Thread Types

JIC

BSP

NPT

JIS

Metric/DIN

ORFS

AN

Common Materials of Hydraulic Fittings

Carbon Steel

Stainless Steel

Brass

Aluminum

Applications

Selecting The Correct Hydraulic Fittings

Size

Temperature

Application