Hydraulic Thread Types & Uses

Hydraulic Thread Types & Uses

There are two main types of threads widely used in the industry defined by the nature of the thread form.
– Tapered (Pipe) Threads
– Parallel Threads

Tapered (Pipe) Threads

Pipe threads, as the name suggests, were first invented to join pipes together. These threads take a tapered form achieving a metal-to-metal pressure tight seal when assembled. Most common tapered threads used in the industry include NPT (National Pipe Taper), BSPT (British Standard Pipe Taper) and Metric Taper.

One of the limitations with some tapered threads such as NPT is that when assembled, the gap between the threads of the male and female connectors will leave a leak path. Therefore, a thread sealant will be required to achieve a leak-free seal. Thread sealants will fill any gaps and imperfections of the thread to enable full contact and makes it easy to assemble averting any galling effects.

Common thread sealants used in industrial applications include Teflon thread tape and chemical sealant. Teflon tape is a non-sticking tape that is easy to apply on the thread surface without damaging the thread. However, the tape is prone to tear while assembling which could lead to clogging and contamination of hydraulic systems. Therefore, care must be taken to apply the tape in the direction of the thread so that it would not unravel and tear while assembling. Chemical sealant minimises the likelihood of system contamination but can have its own drawbacks due to incompatibility with connector material, temperature limits etc.

There are however modifications to the tapered thread such as NPTF and NPSM with modifications in thread crest and root design to facilitate full contact between the surfaces establishing a seal without thread sealant. Although, these types of threads may also require thread sealant to achieve complete sealing of the joint.

When designing connections with tapered threads, following limitations should be considered:

  • Lack of sealing in larger thread sizes
  • Not ideal for dynamic pressure systems
  • System clogging and contamination due to sealant
  • Galling

Parallel Threads
Due to its reliability and ease of maintenance, parallel threads are often chosen as the preferred connection method in hydraulics.

The prime function of parallel threads is to facilitate a joint (hold) between two connectors. A sealing method will need to be accompanied to complete a leak-free connection. Therefor the following sealing methods are present in connectors with parallel threads.

  • Metal Seal
  • Soft Seal

Metals seal type connectors achieve sealing by means of a machined face on one connector and a matching, inverted face on the mating connector. These machined “seats” provide better sealing compared to traditional tapered connectors and more importantly, no thread sealant is required.

Common seat angles featured on connectors are 30° (e.g. BSPP), 37° (e.g. JIC), 45° (e.g. SAE).

RYCO Hydraulics is dedicated to delivering effective solutions to our customers. Our team identified the need for a JIC fitting that equals or betters the performance of ORFS. Through extensive research and development, RYCO is proud to launch to offer the new and improved JIC fitting – JSEAL™.

RYCO JSEAL™ redefines the benchmark for fitting technology, delivering double the torque, double the strength and double the working pressure of JIC standard fittings. The design of RYCO’s JSEAL™ drives unrivalled performance, eliminating sweating, cracking, and stretching, while simplifying installation – we guarantee it.

For port applications, soft seal connectors are used due to their ability to retain sealing at high pressures and vibrations.

Soft seal connectors feature an elastomeric material such as O-Ring, Encapsulated Ring or bonded washer. Some of the widely used soft seal connections include SAE Code 61 / 62 Flange, ORFS and UNO.

For an overview of the different hydraulic connector types, check out Hydraulic Connectors 101.

Want More Information?

If you would like to know more about hydraulic connectors, contact our RYCO Hydraulics Customer Service team or fill out our contact form.

How Can RYCO Thread ID Mate Application Reduce Downtime For Hydraulic Specialists?

How Can RYCO Thread ID Mate Application Reduce Downtime For Hydraulic Specialists?

Are you a time poor hydraulic hose technician, workshop owner, hose assembler or Mobile Connector Specialist (MCS)? If so, RYCO Hydraulics has recently developed an advanced, time-saving solution – RYCO Thread ID Mate application.

Gone are the days where you find yourself spending hours identifying hydraulic threads. Our easy to use and completely free application is ready to download:

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Only launched in May 2020, RYCO Thread ID Mate application is already proving to be the perfect on-the-go solution for hydraulic specialists, with over 2,000 downloads from both iOS and Google Play users.

What are the major benefits of RYCO’s Thread ID Mate application?

  • Identify internal and external hydraulic threads and connectors on the go – in your mobile truck, at your store counter!
  • Free and easy to download onto your iOS and Android devices.
  • Decrease your safety risk by identifying the correct hydraulic thread for your hydraulic application.
  • Simplify the process of identifying hydraulic connectors. No more confusion when selecting hydraulic threads. RYCO’s Thread ID Mate application provides an intuitive and simple identification process to help you find detailed information about threads specifications (like BSP, NPT, JIS, ORFS, SAE), sizes and more!

Maximum uptime decrease downtime coupled with improved knowledge about hydraulic threads – less stress is certainly guaranteed with RYCO’s Thread ID Mate application!

Please, provide us with your feedback as your opinion truly matters. Let us improve your experience:

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Want more information?

To find out more about the RYCO Thread ID Mate application and have thread identification at your fingertips, contact RYCO Hydraulics.

Hydraulic Connectors 101

Hydraulic Connectors 101

As the name suggests, hydraulic connectors are used to connect hydraulic circuits by joining two different end terminations together and creating a flow passage to ensure fluid transfer.

Hydraulic connectors can be grouped into three main types:

  • Internal Thread
  • External Thread
  • No Thread

Internal and external threaded connectors are also known as female and male, respectively.

There are many thread standards in the industry primarily based on the country / region of origin. BSP (British Standard Pipe), NPT (National Pipe Tapered), UN (Unified Inch Screw Threads) and Metric to name some of the most common.

To avoid damage to hydraulic systems, selecting the right type of thread is very important.

Common variation in fitting designs are outlined below that is useful in thread identification.

Tapered / Parallel Threads

Some threads have a tapered thread surface, such as BSPT, NPT (denoted by letter T) whereas others are parallel. BSPP, UN are examples for parallel threads.

Tapered threads are designed to seal on the thread surface.

Sealing of Hydraulic Connectors

Along with tapered threads, other sealing methods include:

  • Metal Seal
  • Soft Seal

Metal seal type was developed to maximise sealing of a connector under pressure. Connectors that have this sealing method will include a machined cone seat (convex or concave) that will seal with the corresponding male / female connector.

Common seat angles include:

  • 30° cone seat (BSPP, some Metric fittings)
  • 45° cone seat (SAE fittings)
  • 37° cone seat (JIC fittings)
  • 24° cone seat (Metric fittings)

Some connectors are designed to seal using elastomeric seals, natural or synthetic to prevent leakage. This type of sealing method is common with adaptors intended for port use, where a soft seal on the base of the adaptor will seal with the flat surface of a port.

Soft seal connectors can be seen on the face of male fittings and adaptors (such as ORFS) which will establish a seal with a flat surface on a female fitting of the same size.

Thread Size, Thread Count & Pitch

Thread size is designated by the external major diameter of a thread that can easily be measured using a calliper. The actual measurement is generally slightly lesser than the nominal thread size. Imperial thread sizes are expressed in inches and metric thread sizes in millimetres paired with “M” (e.g. M6 for 6mm).

Thread count (also known as Threads Per Inch – TPI) and pitch are also important factors when identifying threads and are usually stated along with the thread size.

TPI is common with imperial connectors which basically is the number of threads within an inch measured lengthwise.

For metric threads, pitch is used instead which means the distance between two crests of a thread in millimetres.

How to Identify Connectors?
RYCO’s Thread ID Mate application provides an intuitive and simple identification process to help you find detailed information about threads specifications, sizes and more.

Hydraulic threads can be identified using a few simple steps using the Thread ID Kit and RYCO Thread ID Mate application.

  1. Determine the thread type:
    Visually inspect to determine if the connector has and internal or an external thread (if any).
  2. Is the thread tapered or parallel?:
    Tapered threads can be identified by visual inspection or placing a straight surface, such as a ruler, next to the thread to compare the difference in diameter at the shoulder of the fitting to the diameter at the tip.
  3. What type of sealing face / method does the connector have?:
    Check if the connector has a conical sealing face or a flat sealing face, and whether a soft seal is present.
  4. Using Vernier Calipers included within the RYCO Thread ID Kit, measure the outer / inner diameter of the thread:
    Measure the ID / OD of the connector across flats of the Vernier Calipers for better accuracy.
  5. Determine the sealing face seat angle (if any):
    Align the seat gauge of the Thread ID Kit with the seat of the connector and identify the angle that matches with the seat.
  6. Find the pitch / TPI:
    Use the thread pitch gauge to find out the exact pitch / TPI and verify the thread.

RYCO Thread ID Mate offers you a guided, user friendly process to identify connectors quickly and efficiently.

The Thread ID Mate application is available for your Android and iOS devices. That’s thread identification you can keep in your pocket.

Want More Information?

If you would like to know more about hydraulic connectors, contact our RYCO Hydraulics Customer Service team or fill out our contact form.

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