Griplok® tube fittings use a proven dual-ferrule compression seal to provide leak-tight connections and are especially suited to applications with high vibration such as gas transmission and turbines. They are designed, manufactured, quality controlled and distributed to be totally “interchangeable” with the Hoke® Gyrolok® brand of tube fittings.

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  • MAWP: 12,000 psig*
  • Temperature Range: -325 to 1200°F
  • Materials: 316 SS, Alloy 400, C-276, and brass. 
  • Sizes: 1/16 to 1 in.
  • Adapters: NPT, ISO/BSP, SAE/MS, AN, weld, O-seal, tube stub, port connectors, hose, and ORFS.
  • Shapes: Straight, elbows, tees, crosses, caps, plugs
  • Special fittings: Bulkhead and extended (long), bore through, positionable, calibration and dielectric fittings.
  • Accessories: Stop collars, bulkhead locks, nut and ferrule sets, tools and accessories

*Griplok tube fittings are rated to the maximum allowable pressure rating of the tubing they connect.


Griplok tube fittings use a two-ferrule design with sophisticated geometry, precise machining, and unsurpassed material quality, to provide leak-tight remakeable seals even in applications having high vibration and extreme temperature changes. This leak-tight seal is the result of the sequential interaction of the nut, the front and back ferrules, the body, and the tubing.

The simple geometric rotation of the Griplok nut provides the axial thrust necessary to "coin" 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 tube.

During the rotary movement of the nut, the internal surface of the nut meets with the rear surface of the rear ferrule to axially move the rear ferrule forward against the back radius of the front ferrule. Simultaneously, the front ferrule is driven forward into the angular section of the fitting body to form a primary metal-to-metal seal. The rear ferrule roll-in locking action occurs on the outside diameter of the tube to complete the sealing action and secure the tube within the fitting. The controlled ferrule drive prevents body distortion and helps compensate for exposure to system variables such as vibration, pressure pulsation and thermal expansion or contraction.

Intermix and Interchangeability

Griplok tube fittings are designed, manufactured, quality controlled and distributed to be totally “interchangeable” with the Hoke® Gyrolok® brand of tube fittings. The precision manufacturing of both products to stringent tolerances under rigid quality control procedures ensures the safety, performance and reliability of service whenever Gyrolok and Griplok tube fittings component parts are mixed and used in accordance with published installation and service practices.


Griplok tube fitting straight configurations are machined from type 316 stainless steel cold-finished bar stock in accordance with ASTM A-276 and ASTM A-479. Elbows, tees and crosses, are machined from close-grained 316 stainless steel forgings in accordance with ASTM A-182. All 316 stainless steel. All components are heat code traceable. Certified material test reports (CMTRs) are available on request.


Griplok tube fittings are completely assembled and individually bagged to assure the highest levels of quality and cleanliness. The protective bags eliminate contamination (tubing burrs, dirt, etc.). They are packaged in convenient, small-lot quantities for easy procurement and handling. Box labels are color-coded according to the tube fittings’ material. Labels include the part number, material, product description and picture of the product.

Tube Fittings Installation Training

SSP and SSP distributors provide extensive installation training. Courses cover:

  • Intermixing and interchanging
  • Swaging and quality assurance
  • Remaking and reusing tube fittings
  • Handling cutting and preparing tubing
  • Tube bending

Quality Certification

Griplok tube fittings are manufactured in accordance with SSP’s Quality System, which has been certified to conform to the ISO 9001:2000 Quality Standard. In addition, all fittings are manufactured to the technical design specifications and rigid quality control standards of the SSP Instrumentation Division. SSP’s continuing commitment to quality is reflected throughout the company in its personnel, policies, equipment, products and service.


Griplok tube fittings have been tested and approved by the following organizations:

Tools and Accessories

SSP offers tools and accessories to support Tube fitting assembly and installation and tube cutting, preparation, and bending. See more about tools and accessories.