A Dresser Style 65 Compression Coupling is a simple, reliable and widely used pipe connection designed for low-pressure industrial and plumbing applications. These fittings are known by several common names such as compression coupling, compression fitting or galvanized Dresser coupling. They provide a quick, weld-free and thread-free solution for connecting two plain-end pipes.
Style 65 couplings are typically used in systems operating at or below 150 psi, making them a popular choice for light industrial service, water lines, general plumbing and applications where a clean, easy-to-install connection is preferred. Because they rely on basic mechanical components instead of threaded or welded joints, they are ideal for situations where convenience, speed and reusability matter.
Key Components of a Style 65 Coupling
A Style 65 Compression Coupling consists of a few essential parts that work together to form a tight seal around the pipe. Each component has a specific role in ensuring proper function:
Nut
The nut provides the tightening force that compresses the gasket and retainer cup. When the nut is tightened evenly with a wrench, it forces the gasket to press against the pipe surface, creating a seal.
Gasket
The gasket is the main sealing element inside the coupling. Made from resilient material, it expands as pressure is applied, forming a leak-free barrier around the pipe. The gasket must be oriented correctly for proper sealing.
Retainer Cup
The retainer cup sits behind the gasket and helps maintain its position during tightening. It ensures that the gasket stays aligned and compresses uniformly as the nut is tightened.
Coupling Body
The central body holds the pipes in place and creates the housing where the sealing components operate. It forms the main structure of the connection.
How these parts work together
When assembled, the nut pushes the retainer cup, which in turn compresses the gasket. This compression creates the seal. The simple construction and minimal component count make the Style 65 ideal for low-pressure applications where ease of installation is important.
How a Style 65 Compression Coupling Works
The working principle of Style 65 couplings is straightforward and highly practical for field installations.
Step-by-step:
Slide the nut onto the pipe.
Place the gasket and retainer cup in the correct orientation.
Insert the pipe into the coupling body.
Leave a small gap between the pipe ends-typically 1 to 1.5 inches-to prevent over-insertion.
Tighten the nut evenly using a wrench to compress the gasket and create the seal.
Importance of the pipe gap
The gap allows the pipe to sit correctly within the coupling without pushing components out of alignment. It ensures the sealing elements compress properly on each side.
Axial pullout limitation
A key limitation of Style 65 is that it does not prevent axial pullout. This means if excessive force pulls directly on the pipe, the coupling may not hold it in place. It seals extremely well but does not act as a mechanical restraint. If pipe movement or pullout is expected, a Style 90 coupling with a lock ring is a better choice.
Pressure Rating and Limitations
The Dresser Style 65 coupling is rated for 150 psi, making it suitable for:
Water lines
General plumbing
Light industrial flow
Temporary or permanent low-pressure connections
It should not be used in high-pressure or high-stress installations. When pressures exceed 150 psi or when pullout resistance is necessary, upgrading to a heavier-duty connection such as a Style 90 compression coupling is recommended. Style 65 excels in cost-effective, low-pressure tasks where watertight sealing is the priority.
Available Configurations in Style 65
Dresser Style 65 couplings come in multiple configurations to match common plumbing and industrial needs.
Straight Coupling
The most common version, often seen in 1-inch size. It joins two straight pipe sections end-to-end. Ideal for repairs, extensions and replacement work.
Style 65 Elbow
A 90-degree version used when pipes need to change direction. The sealing principle is identical to the straight coupling but shaped to accommodate corner installations.
Style 65 Male Adapter
This component connects a threaded pipe or fitting on one end and a compression connection on the other. It’s helpful when transitioning between threaded systems and non-threaded piping.
Style 65 Insulating Adapter
This specialized adapter connects nominal pipe to copper tubing. The internal step / lip ensures proper insertion depth, preventing over-insertion and ensuring a proper seal. Widely used in water lines, retrofits and plumbing repairs where material types differ.
Installation Guide for Style 65 Couplings
Tools Needed
Adjustable wrench
Pipe marker
Vise (optional for bench assembly)
Step-by-Step Installation
Prepare and clean pipe ends
Slide nuts onto the pipe
Insert gasket and retainer cup in correct orientation
Push the pipe into the coupling leaving a proper gap
Tighten nuts gradually and evenly
Repeat sealing process on both ends
Apply pressure and check for leaks
Tips for a Reliable Seal
Make sure the gasket lip faces inward
Ensure retainer cups are not reversed
Tighten gradually to avoid gasket distortion
Inspect under pressure to verify sealing performance
Where Style 65 Couplings Are Commonly Used
Style 65 compression couplings are preferred in:
Light industrial fluid systems
Domestic and commercial plumbing
Water distribution and service lines
Mechanical systems requiring quick repair
Low-pressure connections where welding is not preferred
They are especially useful in maintenance jobs, temporary installations or situations requiring fast assembly without heat or threading.
Style 65 vs. Style 90: When to Use Each
Style 65
Rated for 150 psi
Standard sealing, no lock ring
Suitable for low-pressure work
Style 90
Higher strength and 300 psi rating
Includes lock ring for axial restraint
Suitable when pullout is a concern
This comparison helps users choose the right coupling based on pressure, pipe movement and installation environment.
Maintenance, Spare Parts and Replacement
Many installers keep spare gaskets, nuts and retainer cups on hand because these components experience normal wear over time. Signs that replacement is needed include:
Drips or moisture around the seal
Gasket hardening or cracking
Reduced ability to tighten fully
Wear from repeated assembly/disassembly
The simplicity of the design makes maintenance straightforward and cost efficient.
Summary
The Dresser Style 65 Compression Coupling is a simple, proven and effective solution for low-pressure pipe connections. It provides:
Easy installation
Reliable sealing up to 150 psi
Multiple configurations
Compatibility with both steel pipe and copper tubing (via adapters)
It is ideal for water lines, plumbing repairs and light industrial applications.
If you need Style 65 couplings, elbows, adapters or replacement parts, you can explore Trupply’s full range of compression fittings. Our selection includes standard couplings, 90° elbows, male adapters and insulating adapters designed for dependable everyday use.
Hello. Today we are talking about Dresser style 65 coupling. They are also called Dresser compression coupling or compression fitting or galvanized Dresser coupling. This is a standard, 1 inch style 65 coupling, this is how it looks like. This is a style 65 coupling elbow and a style 65 male nut.
Let me show you the component of these. If you open it up, and these are very simple to assemble, you can see that they have a gasket on both sides and the gasket, if you look here, has a retainer cup. This is a retainer cup, this is a gasket, and that’s how you put it together. Style 65 is 150 pound coupling, they are not good for more than 150 psi, used for light industrial application, light plumbing application; a place where you don’t want to thread, you don’t want to weld, you can use a compression fitting.
Let me show you how this goes together. Again, very simple. You just pass on the nut from one side, the gasket on the other side, and this goes like this, and that’s how you make a connection. Same thing on this side, slide the nut, make sure the retainer cup is on the gasket, and the lip of the gasket should be pointed inwards. If you just slide it on, and then push this thing on, and that’s how you make it. The better practice is that you want to leave a slight gap in the middle, so you should mark your pipe, make sure that you don’t push the one side too much. Leave about an inch, an inch and a half gap in the middle so this pipe will come all the way up to here, this will come all the way up to here, and you can just adjusted. Then, once you take a wrench and once you tighten it up, then it will create a seal. Remember, these type of coupling will not prevent a pipe pullout. If you have a situation where the pipe can pull out, then there is another solution. You can use a universal style 90 coupling that comes with lock ring, but they are generally used in an application where the pipe pullout is not an issue. Slight movement is okay, but don’t expect a lot. If there’s a lot of axial force, then this thing can come apart.
This is a style 65 compression elbow. This works on the exact same principle as the coupling, you just put one pipe right here, you put the other one right here, and it creates a seal. Remember, the style 65 coupling does not prevent an axial pullout, so if you have something pulling the pipe out, it will not prevent it; it just seals gaps the pipe. It holds it a little bit, but don’t expect a lot of pullout resistance. Again, to show you, this is the exact same thing. This is the nut and it has a retainer cup and the gasket. This is how it looks like, the gasket, the retainer cup, and the nut. Trupply also sells the spare parts, so if you have this in an installation, you want to replace the nut or the gasket or the retainer cup, we sell those separately also.
This is a style 65 compression coupling adapter, it’s also called a male adapter. It helps you connect to a threaded fitting and have a compression fitting on the other end. So if you have a threaded coupling, you can thread this on and then the other side now becomes a compression coupling in the similar fashion that you use the coupling. You slide the nut, put the gasket, and then you have a compressed coupling on this end.
This is an insulating adapter. If you are connecting a nominal pipe to a copper pipe or copper tubing, then you will use this insulating adapter. The way this thing works is you will have a regular coupling connection right here, imagine this is all made up, and on the other side, you will just drop this thing in, you have to make this loose, drop this thing in, and then you will slide your copper tubing through here. Once you tighten the nut, it will grab onto the pipe. What it helps is this copper tubing dimensions are different than nominal pipe dimensions. It helps collect a 1 inch regular pipe to a 1 inch copper tubing through the use of this insulating adapter. The way it works is, it’s hard to see from here, but it has a little lip so you don’t have to worry about it. You just make sure the opening end is facing outside and the little step on the inside, so once you drop the tubing in, it will just stop. It’s very simple to install, you just put this one in and then slide this onto your copper tubing, put this other thing here, and then, once you tighten the nut, it will grab onto it and it will make a compression fitting. Style 65 insulating adapter to join regular pipe to a copper tubing.
In summary, this is style 65 Dresser compression coupling, also called compression fitting. This particular one is 1 inch and this is available in a coupling, in a 90° elbow, in a male adapter, an insulating adapter to compensate for a difference in size from a regular pipe to a copper tubing. So if you want to connect a regular pipe to a copper tubing, slide this on on one end, put the copper tubing on and then you have a compression coupling that can be used on a copper tubing. Again, the components are very simple, you have a nut, and then you have a gasket and a retainer cup, and that’s what creates the sealing element. Remember style 65 compression coupling has 150 pounds psi pressure rating, generally for lighter application, water application, light plumbing industrial application. Style 65 compression coupling will not prevent a pipe pullout, so if you are in a situation where you think the pipe may pullout, then this might not be a good use. Thank you.
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Trupply filled my order perfectly as specified. The response was excellent! I do not often order pipe fittings as I run a small custom shop, however, I will be back to Trupply in the future!
The fitting arrived quickly and was as expected and advertised. Would buy from this site again. I will say it is a shame that the shipping cost exceeded the cost of the fitting.
