What’s the difference between fastening into timber and steel?

Fastening to timber substructures

In order to achieve high load-bearing capacity values in timber, the screws have a coarse thread. This is characterized by a large pitch and a large depth of bevel in the thread geometry. EJOT screws from the JA series are an example of this.

 

Fastening in steel substructures

For use in thicker steels, however, screws with a finer thread geometry are necessary in order to form a fine thread. The EJOT JZ3 screws can be named here as an example.

In the case of fasteners for steel substructures, a distinction is also made between two "point styles". The JZ screws have a dog point at the bottom – that is, a dulled end – while the JB screws have a point. The latter are suitable for thinner steel substructures, as the point is better positioned in the pilot hole.