The HYTORC Washer is an accessory that greatly improves torque tightening operations in the three areas of safety, quality and speed by allowing tightening without a reaction arm.

  • Safety: By using the Reaction Washer, the reaction arm is no longer required and therefore eliminates a major risk to the operator.
  • Quality: The HYTORC Reaction Washer allows an axial tightening without reaction arm and distributes the reaction force on its circumference which cancels the shearing stress due to the conventional reaction arm.
  • Speed: to position a tool, whether it is a hydraulic wrench or a torque wrench, on a fastener equipped with a reaction washer, the operator can choose the orientation that suits him best without having to worry about finding a solid and fixed reaction point.

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Features of the HYTORC WASHER Reaction Washer

  • Sizes available from M14 to M80 (and same range in inch dimensions)
  • Thickness equivalent to conventional washers
  • Standard AISI 4140 material (also available in STAINLESS STEEL)
  • Hardness 38 to 45 HRC
  • Reusable for Temperature
Reaction washer - Hytorc France

Technologies of HYTORC Washer Reaction Washers

The main objective of these HYTORC Reaction Washers is to eliminate the need for a reaction arm in torque tightening operations whether using hydraulic wrenches or torque screwdrivers.

The reaction arm, which is indispensable in conventional torque tightening and loosening, has several disadvantages that can be avoided.

In the same way as a conventional flat washer, the reaction washer offers a precision-machined, smooth and hard surface limiting friction from the nut or screw head while its other side is ribbed to grip into the material and contain the reaction counterforce.

These locking washers are equivalent in thickness to conventional washers and replace them without having to order longer screws for deployment at no additional cost. HYTORC WASHER reaction washers can be used with both pneumatic screwdrivers and pneumatic screwdrivers.

Operator safety

The major risk of injury when tightening to torque with torque tool is due to the reaction arm or heel.

With the Hytorc Washer reaction washer, we use a bell (driver) which consists of 2 elements: a conventional bushing on the inside and an outer bell which has a chiselled indentation at its base which takes up the external shape of the steel washer. The bell thus rests on the contour of the washer and holds the wrench or screwdriver frame by the coaxial grooves.


With the tightening tool held in place, it can develop its torque as if its reaction arm were in support. The advantage is that there’s no risk of getting trapped between the reaction arm and its fulcrum.

The reaction arm is held in place by the coaxial splines.

The reaction arm on conventional torque tools is a moving part that prevents the screwdriver or wrench from turning around the bolt when it is actuated. It is preferable for the reaction arm, or reaction heel for eye wrenches, to be in support before starting the machine, as otherwise the operator risks injury by pinching or crushing if his hand is between the arm and a fixed part, as the force involved at the point of support is considerable.


For a tool developing 1000 N.m for example, this effort is of the order of 1Tonne so the danger to fingers and hands is serious. And using HYTORC reaction washers increases operator safety by completely nullifying this risk.


Reaction washer - Hytorc

Torque quality with the WASHER reaction washer

Torque tightening with conventional tools presents tightening quality drawbacks that are mainly due to the reaction arm or heel.

Because of the distant reaction support, the tightening operation presses the screw or threaded rod against the edge of its through-hole and introduces shear stress into the bolt.

By concentrating forces in the bolt axis thanks to the reaction that is taken on the whole washer contour, this transverse stress is eliminated thanks to a homogeneous effort around the nut which increases tightening precision, reduces wear on threads and bearing surfaces.

With the use of HYTORC WASHER reaction washers the tightness of pressure vessels is better controlled and there is a reduction in the variation of bolt load on the flange. Tightenings close to the elastic limit are less likely to exceed it.



When you use a HYTORC WASHER reaction washer on a bolted assembly, the bolting process is intuitive, you no longer have to worry about how to orient the hydraulic wrench or torque wrench so that the reaction arm is in support.

We place the tightening tool directly on the bolt as it’s most convenient for us to do so knowing that the chiseled shape of the bell will quickly find a position on the corrugated contour of the metal washer to start tightening or loosening.

The footprint of the tool with bell is smaller and above all more gives a better balanced weight than with a conventional reaction arm so it promotes operator productivity to quickly move from one bolt to another.