5 Ways to Identify Hydraulic Threads

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Take a look at a standard garden hose. Its threaded fitting slips right onto most faucets because of its universal size. This convenience allows you to buy any hose and it’ll fit every time. Consider the world of hydraulics, and the fittings are completely different. They’re certainly threaded, but sizes can widely vary. Learn how to identify hydraulic threads with a few simple methods. You’ll save your system from potential problems as a result.

1. Compare Parallel With Tapered

Your choice of hydraulic thread is just as critical as comparing hose typesbefore installation. Most fittings come with one of these types of threads, including:

  • Parallel
  • Tapered

Take a look at each fitting’s profile. A parallel fitting has the same diameter down the entire length of its threads. It looks like a small cylinder.

Tapered fittings have thread diameters that diminish as the thread’s end comes to a rough point. This determination doesn’t require any tools, which makes it the easiest step to take as you identify the parts. You’ll narrow down your search for a replacement fitting with this step alone.

2. Look at Pitch

The threads on any fitting will have a certain pitch or angle to their arrangement. The pitch will determine the number of threads found on the fitting.

Pull out a pitch gauge and carefully press it against the threads. The proper gauge will latch right into the threads’ valleys.

To ensure a strong fit, look at the gauge and thread up against a lighted background. You shouldn’t see any light between the two items when the gauge is correct. Continue to switch out gauges and adjust the teeth. You’ll find a match that identifies the thread in no time.

3. Examine Pipe-Thread Size

Another clever way to identify threads is through a pipe thread chart. Be aware that only a few pipe thread types will fall under this designation, including:

  • BSPT
  • BSPP
  • NPT/NPTF

Your fitting may not have these details, so turn to a nominal size profile chart. Match your thread to the chart.

You can also use your fitting’s outside diameter as a reference point if a pipe thread chart isn’t available. Subtract a quarter-inch from the diameter’s size to find the nominal size. Use this value as a reference point during sizing. Don’t forget to round off your value if your calculations come with several decimal places.

4. Know Non-Pipe Sizing

When it comes to non-pipe hydraulic fitting types, identification comes down to measurements. Ordering a fitting guideis a simple way to narrow down your identification process. If you work in the hydraulic industry, these reference booklets should be available throughout the facility.

Figure out your non-pipe size by pulling out a pair of calipers. Measure the outside diameter of the hydraulic threads. This value will ultimately identify the fitting.

If you look through the reference pages and find no matches, verify the measurement again. The caliper may be off, or you have one of the many pipe thread types in your hand.

5. Break Down the Industry Lingo

The reason why hydraulics are so effective in a closed system is because the pressure involved is always equally applied in every direction, states Hydraulics & Pneumatics. Because of these known pressure values, specific types of threads must be used to protect the system’s integrity.

To simplify the identification process, manufacturers created an industry standard. You’ll know the exact dimensions of a hydraulic thread if you know its designation, such as:

  • M size
  • R size
  • G size

Use these reference points to identify threads with confidence. The industry standard remains fixed so that mistakes are minimized during installation!