HEX WASHER SELF TAPPING SCREWS 18 SERRATION TYPE F
The underhead knurling has two distinct functions. Once the screw has been tightened, the indentation causes the unscrewing torque used to be greater, making the fixing more stable in all those applications which are subjected to movements and / or vibrations during their use. In the electric field, however, the indentation scrapes the surface of the metal, effectively creating connectivity with the material where grounding is required. However, it must be taken into account that the serration can never replace the tightening of a screw with the serrated washer, which is much more performing in itself.
Compared to the cross recess, the hexagonal head guarantees the possibility of applying a higher tightening torque without the risk of the insert coming out. It is particularly suitable for diameters from 4.8 upwards.
The length of the screw is measured from the tip to the underhead.