Special Features of Self-Drilling Fasteners

After we have looked at the two types of screws, we would like to conclude with a few special features of screws for industrial lightweight construction:

 

Diameter 

Screws for industrial lightweight construction usually have a diameter of 4.8 mm to 8.0 mm.  

 

Undercut

Screws with an undercut are used for thin sheet metal connections. This is a section directly under the screw head that has no thread. This section minimises stripping of the sheet metal, which can mean a loss of load-carrying capacity. In addition, it offers turning-back protection, which prevents unintentional loosening of the screw and a loss of tightness of the roof.

Reducing Swarf

Swarf is usually produced with both self-drilling screws and self-tapping screws. This swarf must be removed in a separate work step in order to prevent rusting. The self-drilling screws with reduced swarf therefore represent a further stage in the development of self-drilling screws. Pre-drilling of the construction or cutting of a thread is not necessary here. The screws of the EJOFAST® family can be mentioned as an example. The unique tip geometry of the EJOFAST® self-drilling screws penetrates thin sheet metal with reduced swarf, resulting in significantly reduced cleaning effort. Self-drilling screws with reduced swarf are ideal for thin sheet metal connections or fastening sheet metal to wood.

 

Material

In addition to self-drilling screws made of heat-treated steel, the screw parts often consist of two different raw materials. These are so-called bimetal screws. The screw head, shaft and thread are made of rustproof stainless steel to ensure a permanently corrosion resistant connection. Since the stainless steel does not achieve the necessary hardness to penetrate steel components, the drill point is made of hardened steel.

In this post, we have now learned about two different types of screws with their respective properties and special features. In the next part of the guide to self-drilling screws you will find information about the drive and the different head styles of self-drilling screws.