FK Series Tube Fittings vs. Cone and Thread Fittings
Discover how Swagelok® FK Series tube fittings simplify medium-pressure tubing installation compared to traditional cone and thread fittings. In this side-by-side demonstration, you'll see how the FK Series streamlines the assembly process using basic tools while eliminating many of the preparation steps associated with cone and thread connections. Watch as the FK fitting is installed approximately five times faster, helping reduce labor time, minimize opportunities for installation errors, and virtually eliminate rework caused by minor flaws. The video also highlights how FK Series fittings help reduce contamination risks by avoiding the lubricants and metal shavings commonly generated during coning and threading operations. Learn why engineers and technicians rely on FK Series fittings to achieve faster installation, consistent performance, and dependable leak-tight connections in demanding fluid system applications.
Video Transcript
In this video, you will see a side-by-side installation of Swagelok’s FK series tube fittings and traditional cone and thread fittings.
An FK series fitting is installed on the left. Cone and thread installation occurs on the right, shown at two times the speed.
Right away, you will see that FK series fittings can be installed with just a common wrench, vise, and inspection gauging tools.
On the right, the installer prepares the special tooling required to make a cone and thread fitting.
As the cone and thread installer prepares the tube, the FK series fitting installer simply threads the FK series fitting cartridge into the body and removes the plastic arbor from the end of the nut.
While the cone and thread installer applies the cutting lubricant, the FK series fitting installer inserts the tubing into the fitting body and marks the depth to ensure assembly alignment. No special preparation or cutting lubricant is required.
On the left, the FK series fitting installer applies one full turn to complete the connection. Meanwhile, on the right, the installer continues to form the cone on the tube.
The FK series installer checks the assembly with the Swagelok medium-pressure gap inspection gauge. The gauge does not enter the gap, indicating he is finished and the fitting is ready to go.
On the right, the cone and thread installer checks the end of his prepared tube. A deburring operation is required to remove metal shavings. The installer is now ready to thread the tubing. Using cutting fluid, the threading tool is turned clockwise until it is parallel to the ground and the groove on the threading die is facing up. To thread the tube, the installer applies pressure to the tool while rotating it counterclockwise. As the installer threads the tube, metallic debris falls from the installation. When using FK series fittings, installers do not need to worry about shavings or lubricant as a contamination risk.
Proper coning and threading is a skilled process and requires a knowledgeable installer. Inexperience can lead to improperly threaded connections that can leak.
After inspecting the tube for an acceptable surface finish, he slides the fitting gland onto the tubing. Next, the collar is threaded counterclockwise onto the tubing. He continues threading until one to two full threads are exposed on the cone end. Once the collar is threaded onto the tubing, the installer slides the gland nut over the tubing and inserts the tubing with the collar into the fitting body. The FK series integrates most of the individual components within the fitting cartridge. Finally, the installer tightens the fitting to its required torque value. He is finished.
As you can see, the FK installation was approximately five times faster and would have virtually eliminated any rework. The FK series is comparable to a typical Swagelok tube fitting. By drastically reducing installation time and delivering consistent, leak-tight performance, FK series fittings can help deliver significant cost savings.
To learn more about how the FK series can benefit your operation, contact your local Swagelok sales and service center.
