An Example of Threads – How to Identify a Hydraulic Thread

The fine engineers and manufacturers across the world all have their own standard and design for threads, and there are all manner of systems that the passionate factory owner can look at. With regards to hydraulic systems, there are all manner of adapters and fittings, each using its own distinct thread form and sealing method.

How Important is it Knowing Which Thread is Which?

With regards to thread types and sizes, the sealing method will generally be identifiable by its appearance alone. That being said, most thread forms can indeed look identical to the untrained eye, meaning that many people will spend an inordinate amount of time trying to identify specific kinds in the event of equipment changes or repairs having to be carried out.

Being able to identify specific threads for specific repair or replacement jobs is vital. You can cause a lot of damage to a thread if you apply the wrong part to it during an installation process. Such a mistake can easily endanger the seal reliability pressure holding capacity of the adapter or fitting.

One must be able to identify threads in a speedy and appropriate manner in order to maintain a safe and reliable climate of profitability and productivity. One can seriously hinder the smooth operation of their plant or factory through a failure to maintain thread operation in an intelligent manner.

How do I Identify a Thread?

Determining if a Thread is Parallel or Tapered

With regards to BPST and NPT/NPTF, these are your tapered heads. BSPP and UN/UNF are parallel. Then Metric Parallel and Metric Tapered are identified by their names. You can often identify a thread just by looking at it if you know the different types well.

Keep in mind that tapered threads will continue to get narrower in diameter as you continue towards the ending of the fitting, while a parallel thread will continue to hold the exact diameter from the beginning until the end.

It is difficult to identify such fittings sometimes, so you should use a caliper or parallel jaqs in order to make comparison assessments. One excellent way to identify a male parallel thread is to spot the O-ring, or a removal tube nut.

Determining the Pitch

Such a factor can be translated through the usage of a pitch gage, which can make comparisons by precisely calculating and measuring the quantity threads inside a certain distance.

Make sure to make such thread comparisons within a lighted background, along with a pitch gage. As there are quite a few thread pitches that appear to be quite similar, you should try a few gages prior to settling on the best fit.

You should now be able to reduce the possible number of available thread forms down to a very small select number. Most threads will have a distinct pitch, and in time you will be able to identify such pitches far quicker and more easily, making the entire process far speedier.