How to Select the Proper Compression Fitting
If you need to connect a run of metal or hard plastic tubing, using a compression fitting is a versatile and common solution that’s tried, true, and trusted. Since compression fittings have the ability to withstand high pressure and extreme temperatures, ensuring that you select the right size compression fitting is critical for a safe, tight, and secure fit. And determining the exact fitting size to use is easy. Here are a couple of steps to follow to select the right compression fitting.
Find the Compression Fitting for Your Job
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How to Measure a Threaded Fitting
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To measure a threaded fitting, measure the thread diameter at the widest point across the threads. For a non-threaded fitting, measure the actual insert opening diameter or tube being inserted into the compression sleeve.
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Compare your pipe measurements to the chart below to determine your correct size compression fitting. When the compression fitting has been sized, you’ll need to take into consideration whether any additional piping can be done to make a straight connection or if a directional fitting is needed.
The compression connector family is ideal when working with any rigid tubing, including tubing from fluoropolymers (PFA, PTFE, PEP, PVDF), from other rigid plastics (nylon, polypropylene, polyethylene), and from metals. Compression fittings can also be used with flexible tubing; which will require a tubing insert made from a rigid material that helps the tubing maintain its shape.
| Tube Size | Nominal Size | Female Thread I.D. | Male Thread O.D. | No. of Threads per Inch |
| 1/8" | 5/16" | 17/64" | 5/16" | 24" |
| 3/16" | 3/8" | 21/64" | 3/8" | 24" |
| 1/4" | 7/16" | 25/64" | 7/16" | 20" |
| 5/16" | 1/2" | 29/64" | 7/16" | 20" |
| 3/8" | 9/16" | 1/2" | 9/16" | 18" |
| 1/2" | 3/4" | 11/16" | 3/4" | 16" |
| 5/8" | 7/8" | 13/16" | 7/8" | 14" |
| 3/4" | 1-1/16" | 31/32" | 1-1/16" | 12" |
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| 1/8" Fittings | 3/8" Fittings | 1/4" Fittings |
By following a few simple steps and working with the table provided, selecting the correct compression fitting for the application at hand is as easy as one, two, done! Pair your fittings with the proper metal or plastic tubing and cut that tubing to size with one of our handy tube cutters.
Product Compliance and Suitability
The product statements contained in this guide are intended for general informational purposes only. Such product statements do not constitute a product recommendation or representation as to the appropriateness, accuracy, completeness, correctness or currentness of the information provided. Information provided in this guide does not replace the use by you of any manufacturer instructions, technical product manual, or other professional resource or adviser available to you. Always read, understand and follow all manufacturer instructions.
