Advantages of the
HEICO-TEC® Reaction Nut

  • Space saving
    In contrast to similar products, HEICO-TEC® Reaction Nuts have the same dimensions as the active HEICO-TEC® Tension Nut for the nut body and the washer. This means they do not require any additional space.
  • Reusable
    HEICO-TEC® Reaction Nuts are entirely reusable. The bolted joint will not be damaged during tightening and loosening.
  • Compatible
    HEICO-TEC® Reaction Nuts meet all requirements of ISO 898-2. They can replace any conventional nut with the same strength class as long as they are only reactively loaded and are not used for active tensioning.
  • Elastic
    In contrast to other spring based fasteners such as disc springs or spring washers, which are simply flattened and then ineffective, HEICO-TEC® Reaction Nuts remain elastic up to the maximum bolt force according to ISO 898-1.
  • Durable
    The more elastic a bolt is in relation to the clamped parts, the less stress it will be subjected to. Due to their flexing, HEICO-TEC® Reaction Nuts reduce the load on the bolt and thus increase the durability of the bolted joint.
  • Secure
    Also the more elastic a bolted joint is, the less susceptible it is to untightening and self-loosening. The additional elasticity stored in the HEICO-TEC® Reaction Nuts counteracts preload losses due to settling or creeping. This ensures that the bolted joint remains securely tightened.

The better choice

The HEICO-TEC® Reaction Nut offers decisive advantages over other products:

Hex Nuts

Conventional hex nuts are very rigid and have little elasticity.

In the thread the preload acts in tension, while an equally high compressive force is generated on the contact surface of the hex nut. As a result, the preload force is very strongly deflected in the first load-bearing threads and leads to an uneven load distribution. This is why bolts often break here.

Hex nuts

Spring washers

Each bolted joint (blue) loses preload force ΔF by settling or creeping Δf. Often an attempt is made to increase the elasticity of the bolted joint with a conventional spring washer in order to extend the service life on one hand and to counteract loosening and self-loosening on the other.


Spring washers are already flattened under 50% of the preload force (orange). This renders them ineffective.

Spring washers

Reaction nuts of other manufacturers

Other manufacturers also offer reaction nuts.


They usually have a larger outside diameter and a larger washer than the active tension nut on the opposite side. Therefore they need more space.

Reaction nuts of other manufacturers

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