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Self-breaking <b>nuts</b>


Self-breaking nuts


DIN 980 – DIN 6927
The operating principle applied to all metal, self-braking nuts is characterised by the radial deformation of the thread. This deformation, which is achieved (under strictly controlled conditions) by reducing the thread’s diameter without altering its pitch, makes the nut “self-braking”. When being tightened, the nut returns elastically to its original characteristic, generating a force, which, with the friction created on the thread, results in a braking moment, such as to make the nut “self-braking” for multiple screwing and unscrewing operations. The all metal, self-braking nuts are lubricated with specially designed products that prevent any localised micro-seizing.


DIN EN 7042-7719-10513 (DIN 980 Tipo M)
Self-braking nuts with metal insert incorporate – in the upper section – a special, technically sized, steel (AISI 301) braking washer. The braking washer automatically blocks the top of the thread crest during assembly, thus providing a constant braking moment when being tightened, preventing any localised seizing. The self-braking nut with metal insert achieves outstanding results in vibration and locking tests. Thanks to its braking system, one thread of the screw protruding from the nut is enough to guarantee locking. These nuts can be re-used without damaging the thread or the braking washer and they can also be used at temperatures between -40°C and 300°C, in petrol and oil, without their functionality being affected.


DIN EN ISO 7040-10511-10512 (DIN 982-985-6924-6926 e UNI 7473-7474)
Self-braking nuts with polyamide insert incorporate – in the upper section – a special, technically sized, elastic washer in polyamide 6.6. During assembly, the screw encounters resistance as it moves forward generated by the friction between the thread and the polyamide washer. Polyamide has an excellent elastic return such that the nut in question can be re-used multiple times. It also resists many chemical products used in industry. In certain conditions, such as continuous contact with acidic minerals, strong bases, and sulphuric or chromic acid baths, polyamide will deteriorate. The self-braking nut with polyamide insert retains its characteristics at temperatures between -40°C and +100°C. Beyond 100°C, the use of nuts with metallic braking or with metal insert is recommended.

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