Self braking nuts

All metal according to norms

DIN 980 - DIN 6927
The thread of all-metal, self-braking nuts is radially deformed during use. This deformation, which occurs (under rigorously controlled conditions) by reducing the diameter of the threading without changing its pitch, ensures the nut's self-braking functions: while being screwed, the nut springs back to its original characteristic. This generates a force that, along with the friction created on the threads, causes a braking moment, ensuring the self-braking action during various screwing and backing-off operations. The all-metal self-braking nuts are lubricated with specially designed products that prevent localized micro-seizing.

With metal insert according to norms

DIN EN 7042-7719-10513 (DIN 980 M type)
The top of the self-braking nuts with metal insert has a special, technically-sized steel (AISI 310) braking washer. The braking washer automatically stops the top of the thread crest during assembly, thus generating a constant braking during screwing, and this avoids possible seizing. The self-braking nut with metal insert passes vibration and locking tests with excellent results; thanks to its braking system, one thread of the screw protruding from the nut is enough to guarantee the  locking. They can be reused without damaging the thread and the braking washer. They can also be used within a temperature range of -40°C to 300°C, in various types of petrol and oils without affecting their properties.

With polyamide insert according to norms

DIN EN ISO 7040-10511-10512 (DIN 982-985-6924-6926 and UNI 7473-7474)
The top of the self-braking nuts with polyamide insert has a special, built-in polyamide 6.6 technically-sized spring washer. During assembly, the screw encounters resistance as it moves forward, due to the friction between the thread and the polyamide washer. The polyamide has enhanced spring-back so that this nut can be used over and over again. It can also  withstand numerous chemical products used in the industry. Polyamide deteriorates in continuous contact with strong-based mineral acids, and sulfuric or chromic acid baths. The self-braking nut with polyamide insert maintains its properties within a temperature range of -40°C to +100°C. Above 100°C it is recommended to use metallic braking nuts or those built with a metal insert.

No self braking nuts

Plain flange

DIN EN 1661 (DIN 6923)
The advantages of the flange on the nuts are:
  • a better load distribution on the thread;
  • a smaller wedge effect of the load on the thread (causing the enlargement of the nut and therefore reducing the resistance section on the threads);
  • A reduction of the specific pressure exerted by the load on the support surface.;
  • self-locking effect due to the micrometric subsidence of the flange, this deformation causes some radial components and consequently the tightening of the nut.

Elastic flange

DIN EN 1661 (DIN 6923)
The advantages due to the self-locking flange on the nuts (in addition to the ones already indicated for the flange nuts) are:
  • a small chance of recovery in case of loosening caused by thermal expansion or by settlements.

Knurled flange

DIN EN 1661 (DIN 6923)
The “security device” of the knurled nut is made by teeth, whose forms at rake angle have been duly studied to prevent unscrewing  usually caused by vibrations. The knurled nut is the only one, which requires an untightening force well higher to the tightening one.

Nuts with mobile washer

The nuts with no-loss mobile washer consist of a two-piece rotating assembly (no-loss on request): a hex nut and a washer.
There are many advantages in using the nut with no-loss mobile washer, including:


  • easy assembling  on slots
  • it prevents the user from forgetting the washer
  • it makes assembly easier even in difficult positions (such as for screws facing down)
  • it reduces assembly time
  • it simplifies orders and stock management
  • it does not  ruin the bearing surface since the nut, while being screwed, rotates on the washer,  that remains fixed


The nuts with no-loss mobile washer can be made in various versions:

  • With plain conical washers; The nuts screw on easily until they come in contact with the surface to tighten. Applying the required torque, an elastic deformation is created on the washer, which exerts a pressure on the nut to prevent it from coming loose due to the adjustment of the assembly, vibrations or load losses.
  • With knurled conical washers; The knurled circular ring at the contact point between the nut and washer is the operating principle of this nut. Such knurling is designed to guarantee the elastic characteristics of the washer and to prevent the nut from unscrewing due to vibrations
  • With plain flat washers; The nuts with a washer made with no-hardened and tempered material are used in applications where one or more support washers are required.

These solutions ensure extreme product flexibility since the various combinations of nuts and washers provide the designer with the best solution for any specific assembly.

Nuts and bushing for projection welding

UNI EN ISO 21670
They are manufactured according to the UNI EN ISO 21670 and specifically designed to be welded by projection or capacitive discharge on cold or hot forming metal sheets. Our products have pins in specified area which, fusing as a result of passage of current, allow the welding of threaded component to the main structure. 

We are also able to apply on the internal thread some specific products in order to protect it from welding slag and coating deposits. This in order to ensure the perfect functionality of the threaded connection.

Special nuts

Our team of engineering and the technical department are at your disposal to evaluate together the best solutions for your requests.

Coupling nuts: hex nuts

According to norms DIN 3870 and EN ISO 8434-1 shapes A3, A2, B2, EN ISO 8432-2 (JIC), EN ISO 8434 - 3 (ORFS) and BSP – GAS threads

Crimping nuts

Our technology of cold and hot forging is an important technical innovation if compared with the well-known thread cutting. In fact the plastic deformation of the material gives to our product a greater plasticity during deformation as well as a greater resistance of the rolled thread during tightening.

Brad nuts

Products related to a particular application in the hydraulic field. We have last generation equipment, specially developed and studied by a competent and innovative staff, able to meet the Customers’ requests.

Common Rail

Our latest target fully achieved  is a cold-forged component for the automotive market, especially in the specific power engine with common-rail technology. This product must fulfill high- quality requirements.