DIN 7981 ST 5.5 Stainless Steel A2 304 Pan Head Phillips Drive Self Tapping Screws Cross Recessed ISO 7049

Description

DIN 7981 ST 5.5 self-tapping screw is a screw with a 5.5mm diameter thread that can tap its own hole as it is driven into the material. For hard substrates such as metal or hard plastics, the self-tapping ability is often created by cutting a gap in the continuity of the thread on the screw, generating a flute and cutting edge similar to those on a tap. Thus, whereas a regular machine screw cannot tap its own hole in a metal substrate, a self-tapping one can (within reasonable limits of substrate hardness and depth). For softer substrates such as wood or soft plastics, the self-tapping ability can come simply from a tip that tapers to a gimlet point (in which no flute is needed). Like the tip of a nail or gimlet, such a point forms the hole by displacement of the surrounding material rather than any chip-forming drilling/cutting/evacuating action. Ever Hardware also provides custom-made fasteners & other precision components.

Stainless steel does not readily corrode, rust or stain with water as ordinary steel does. However, it is not fully stain-proof in low-oxygen, high salinity, or poor air-circulation environments. There are different grades and surface finishes of stainless steel to suit the environment the alloy must endure. Stainless steel is used where both the properties of steel and corrosion resistance are required. Stainless steels contain sufficient chromium to form a passive film of chromium oxide, which prevents further surface corrosion by blocking oxygen diffusion to the steel surface and blocks corrosion from spreading into the DIN 7981 ST 5.5 internal structure. Passivation occurs only if the proportion of chromium is high enough and oxygen is present.

DIN 7981 Self-Tapping Screws Size Specification: