GriplokGriplok tube fittings are designed and manufactured to provide a reliable, leak-proof connection in instrumentation and process tubing systems. Griplok tube fittings consist of four precision-machined components:

  1. Body
  2. Front Ferrule
  3. Rear Ferrule
  4. Nut

The double ferrule design, with the staged sequential swaging action of the ferrules during make-up, compensates for the variations in tubing materials, hardness, and thickness of the tube wall to provide leak-tight connections in an extensive range of applications.

Additionally, in fulfillment of the design criteria, all Griplok components are manufactured with stringent tolerances and superior surface finishes under rigorous quality control standards to assure the optimum performance of each component.


Through the critical interaction of precision-machined fitting components with the process tube, a leak-tight seal is achieved.

The simple geometric rotation of the Griplok nut provides the axial thrust necessary to swage the ferrules to the outside diameter of the tube. To eliminate any potential stress on an existing system, the tube fittings have been designed to not transmit installation torque from the tube fittings to the tubing.

During the rotary movement of the nut, the internal surface of the nut meets with the rear surface of the back ferrule to axially move the back ferrule forward against the rear angle of the front ferrule.

Simultaneously, the front ferrule is driven forward into the angular section of the fitting body where the desired “lift to seal” action of the front ferrule occurs. The back ferrule “locks” on the outside diameter of the tube to complete the sealing action and secure the tube within the fitting.

The resulting “engineered gap” between the front and back ferrule is designed to help compensate for exposure to system variables such as vibration, pressure pulsation and thermal expansion/contraction.