How To Measure Threads and Seat Angles for Hydraulic Adapters | Air-Way Manufacturing

How To Measure Threads and Seat Angles for Hydraulic Adapters

Monday, June 24, 2019

Prior to selecting and installing the right hydraulic fittings, it’s important to measure threads. We’ve created this article as a brief outline of the steps necessary to measure threads and what tools are required in order to do so.

How to Measure Threads and Seat Angles for Hydraulic Adapters

If you do need help identifying the right fitting or adapter for your application or as a replacement part, we do offer many different conversion tools (located at the top of our website), and cross reference for other manufacturer part numbers - simply search by your part number or give us a call to verify.

1. Measure Thread Diameter

To measure thread diameter, a combination of O.D./I.D. caliper should be used. Since the threads of a used fitting are prone to wearing and damage, these measurements may not be 100% accurate. A thread chart should be used to match measurements.

2. Determine the Number of Threads Per Inch / Millimeter per thread

In order to determine the number of threads per inch for Inch,  and BSPP threads, a thread pitch gauge should be used. In the absence of a pitch gage, the distance between threads can be measured. 

  • Inch threads are designated in threads per inch.
  • Measuring the distance between threads will identify metric thread pitch.  
  • When using a  pitch gauge it should be placed on the threads until there is a snug fit.

3. Types of Measuring Tools

There are two tools that can be used to measure threads. These tools include an I.D./O.D. caliper (pictured above), and thread pitch gauge, which allow for optimal measurement accuracy.

4. How to Measure Sealing Surface (Seat) Angles

Female seats are very difficult to measure.  For this reason, the manufacturer should be consulted.  If you’re unsure, reach out to us today.

Male connections can be measured by placing a protractor gauge on the sealing surface while making sure that the connection and gauge are parallel to allow for correct angle identification.

Contact Air-Way Mfg for Assistance

For more information on how to measure threads, or if you’re looking for a replacement fitting or cross reference, please let us know by calling 800-253-1036 or reaching out online today.


  • Importance of Pressure Ratings and Testing for Hydraulic Fittings

    It can be difficult to find the right hydraulic fitting or adapter. With so many options available, it can be overwhelming to choose the one that is ideal for your application. While you can simply pick one and hope for the best, we recommend paying attention to pressure ratings as pressure is one of the most important things to consider when you’re evaluating hydraulic adapters and systems.
  • How Air-Way Manufacturing is Using the Internet of Things to Continuously Improve

    As we continue to expand our customer base to top OEMs and distributors worldwide, we are continuously improving our processes and facilities to optimize efficiency and communication with our customers. How are we doing this? We are taking advantage of the internet of things and improving to better serve our customers.
  • Air-Way Canada is Expanding its Inventory

    Since 1977, Air-Way Canada, formerly known as Pacific Hose and Fittings, has supplied high quality hose, fittings and accessory products to customers in Western Canada. Through continued growth and evaluation of market needs, Air-Way Global Manufacturing is expanding its inventory to support the growing customer base in Canada.

Request A Quote

Our online catalog represents only a portion of what we manufacture and offer. We specialize in handling special requests based on your application.

Conversion Tools

Enter a conversion value in any box.

Note: At least two fields must be filled out
Currency - Conversion API currently unavailable. Try again later.

Access Denied

You do not have permission to view this site.