Tapered Thread Port Assembly Instructions for Hydraulic Fittings

Tapered thread  port assembly instructions for hydraulic fittings


No matter what type of port or tube ends your fittings have, it's important to know and use the proper assembly and installation steps. Today we are talking about tapered thread ports, which include NPT/NPTF, BSPT, and metric taper. The tapered threads on these port ends serve two functions: to hold the fitting in place while under pressure, and to serve as the primary seal. Therefore, proper fitting assembly and installation is key to ensuring leak-free tapered thread port connections in your system. 


Watch the video to learn the proper process for assembly and installation of tapered thread ports, or follow the steps outlined below. 

Proper tapered thread port assembly and installation steps:

Step 1: Inspect the components.
To ensure a proper connection, the male and female port threads must be free of burrs, nicks, scratches, or foreign material.

Step 2: Apply the appropriate sealant to the male pipe threads. 
This sealant can also act as a lubricant which is especially important with stainless steel threads because of the potential for galling. To avoid system contamination, leave the first one or two threads from the end of the fitting free of sealants. If you chose to use PTFE tape, be sure to wrap it correctly - 1-1/2 to 2 turns in a clockwise direction when viewed from the tapered thread end.  NOTE: Be sure to chose a sealant based on the application. Pre-applied sealants are often preferred because of the convenience. 

Step 3: Finger tight. 
Once the sealant is in place, screw the connector into the port until finger tight.

Step 4: Wrench tighten.
Wrench tighten the connector to the appropriate turns that are recommended in the Assembly and Installation section of the Parker Catalog 4300. Normally the total number of tapered threads engaged should be between 3-1/2 and 6. Under or over tightening may result if you deviate from this range.  NOTE: If you have a shaped fitting, make sure that it is properly aligned. Remember, never back off tapered thread connections to achieve alignment, as this could potentially cause a leak.

By following these steps, your tapered thread port connections should be leak-free. To help you ensure that all of your hydraulic fitting connections are installed leak-free, Parker Tube Fittings Division has created a series of tube and port end assembly and installation videos for the most common hydraulic fitting connections, which will be shared on over the next couple of months. You can also find detailed assembly and installation information for port end threads and tube fittings in the Assembly/Installation section of our Catalog 4300

Refer to our Tube Fittings Division Frequently Asked Questions page,, for a wealth of information and resources. 

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Burleigh Bailey Engineer at Parker Tube Fittings Division

Contributed by Burleigh Bailey, senior product engineer at Parker Tube Fittings Division




Additional related content about hydraulic tube, hose, and port fitting connections:

Turn vs. Torque? How Making the Right Choice Keeps Your Hydraulic Fitting Connections Leak-Free
How Many Times Can I Reassemble a Hydraulic Fitting?
Tube Routing Tips for Hydraulic, Pneumatic and Lubrication Systems
Tube End Preparation Best Practices for Leak-Free Hydraulic Tube Fitting Connections

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