Hydraulic couplings are the connecting elements between hydraulic lines and hydraulic lines, or between lines and hydraulic components. Hydraulic couplings include hydraulic couplings for hoses and hydraulic couplings for hard pipes. Here we will only introduce hydraulic couplings for hoses. A hose coupling is connected to a hydraulic hose (called the end) and to other components (the end) at the other end. In order to ensure compatibility and leak-free sealing of the connection with other components, the end of the hydraulic hose coupling needs to be designed according to common interface standards. The main purpose of the end is to ensure a long-lasting seal between the coupling and the hose.
I thought I would take a stab at clearing up what is sometimes a confusing decision – which air fittings are right for me? Here are 2 key elements to understand that will help simplify what can be a confusing ordeal.
1. Style:
there are two basic styles of quick-connect fittings – automotive and industrial style. Do we often get asked which style is better? There is no difference in performance or longevity between the styles. It is just a matter of preference. The main consideration is that the two styles are not compatible with one another. The most common frustration for people is when they have existing air couplers and they purchase the wrong style. If you already have air fittings you want to make sure you purchase the same style as your existing fittings. If you don’t know what style you have checked the tip of the male plug (see pictures). The female coupler will give you no clue on what style it is. The tip on the male plug of the industrial style has a bevel or ring protruding outward. The tip of the male plug on the automotive-style is beveled inward; it kind of looks like a spark plug hence the automotive name. Some manufacturers will stamp their disconnect fittings with the product number. Usually, in the product number, there will be an I for industrial style or an A for automotive style. Some contractors who operate multiple crews will use different color air hoses and different styles of fitting for each crew. This way they don’t “borrow” each other’s air hose. There are some universal fittings that will work with either style, but most use a single style fitting.
2. Size:
another question that is often asked is what size of quick-connect fittings does a person needs? The most common size fitting is ¼ inch. This is true for both ¼ and 3/8 inch air hoses. Most 3/8 air hose comes with ¼ inch ends on them, thus most use a ¼ inch air fitting. Another important thing to consider when choosing the right size fitting is what size of thread is your air tool or air compressor. If the size of thread in your air tool is ¼ inch then you will want a ¼” air fitting. The same is true for your air compressor. If the thread size is 3/8” on your air tool then a 3/8” body fitting is what you need. If you are operating a large air tool it may have ¼ or 3/8 inch thread to screw your male plug into. That is why it is important to check. There are air fittings that have a different size body than the thread. For example, you could get a 3/8 inch body air coupler with ¼ female or male pipe thread. These are options but by far the most common is to get the same size body as the thread. If you are running ½ inch hose you will most likely use a ½ inch body fitting with ½ inch male or female pipe thread. If a product number is stamped on an air coupler or fitting usually the first number is the body size and if there is a second number it will be the thread size. If there is only one number that will often indicate that the body and the thread are the same sizes. For example, our product number AC4F tells you that this is an Automotive coupler (AC) that is ¼ inch body (4) and since there is not a second number we know that it has ¼ female pipe thread(F). Here is another product number example – IP6M4. From this product number, we know that this is a male body air fitting with a male pipe thread, but the thread is a different size than the fitting. From the product number, we know that it is an Industrial Plug (IP) that has a 3/8” body (6) with ¼” male pipe thread (4M). If your fittings have product numbers stamped on them you can quickly figure out what size and style you have. You can also Google the product number and that will usually get you the info you need.
Categories: Couplings & Adaptors
Thread sizes are based on trade size rather than actual dimension, which often leads to confusion. Here is our simple guide to measuring a thread and identifying it as a British Standard Pipe (BSP).
The BSP is the UK’s most commonly used type of thread and falls into two categories:
Parallel (BSPP) - also known as G or Rp
Tapered (BSPT) - also known as R or Rc
R, Rp and Rc threads are taken from BS21:1985 pipe threads for tubes and fittings where pressure-tight joints are made on the threads. Meanwhile, G threads are taken from BS2779:1986 pipe threads for tubes and fittings where pressure-tight joints are usually made on a washer or ‘O’ ring.
Using a ruler or vernier, measure across the outside diameter of a male or hose tailpiece thread or measure the inside diameter of a female thread.
I hope this information was helpful. Quick connect air fittings help make working with air tools easy, fun, and saves time. If I confused you just contact us with your question and we will walk you through it. Good luck with your projects!
