021
UNI 6955/B - DIN 7982/F
PHILIPS FLAT HEAD SELF TAPPING SCREWS TYPE F
Self-tapping screws are mainly used for screwing on metal sheets and laminates through simple drilling, without threading or tapping operations. These screws are not particularly suitable for use on die-cast materials and plastic materials. For a safe and stable screwing, particular attention must be paid to the diameter of the hole to be drilled. A small hole in which the screw "forces" to enter is certainly not synonymous with greater guarantee in fixing. It should also be remembered that the existing tables are empirical and only give an indication of perforation, but they are not a certain rule, as the fixing must be checked from time to time according to the technical-mechanical conditions of the particular that will be tighten.
Self-tapping screws without a tip find particular application in pass-through positions, where the screw protrudes from the fixed plates and you want to avoid the risk of accidental injuries caused by the tip coming out. They are therefore accident-prevention in that they reduce the possibility of accidental cuts with the tip even during various maintenance operations.
The screw is measured from the head included to the tip.
