Retrofittable
- Retrofit for Torqued to Tensioning without replacing studs.
- Standard radial footprint as existing nut.
- Replaces existing hex, 12 point, cap,etc nuts.
- One person installation & removal
No Extended Stud Thread Required
- Utilizes the OD of the nut for tensioner gripping surface.
Simple Installation
- Utilized with an External Tensioner (HET) that is removed once tensioning is complete.
Material Substitution
- Nut material can be optimized for higher loads or temperature concerns.

The External Tensioned Nut (ETN) design provides a seamless transition form torqued hardware to tensioned hardware. Until now, it has not been possible to replace torqued hardware with tensioned hardware unless there was a significant amount of thread protruding above the nut. Historically, retrofit has been accomplished by replacing the studs. However with the application of the Riverhawk ETN, this is no longer the case.

The standard ETN design fits inside the clearance envelope of ANSI standard heavy hex nuts resulting in a reduction of flange contact stress. The ETN replaces the existing nut whatever its configuration; hex, 12 point, cap, etc.

In operation, the ETN tensioning system utilizes the nut OD as the gripping surface for tensioning which eliminates the need for a gripping surface on the stud. This makes it particularly well suited for retrofit applications. Once the load cell of the tensioner is applied and the stud is stretched, the retaining ring is turned down and the stud remains loaded. Note that the load cell is removed once tensioning has been accomplished, a factor which results in a lower total cost and eliminates environmental considerations.

If the application requires a smaller envelope or even higher loads in the stud, there are several options available. These options include the use of a washer under the nut to distribute the load and higher strength materials to carry the load with the same factors of safety.