DIN 931 (ISO 4014) defines the partially threaded hexagon head bolt, while DIN 933 (ISO 4017) defines the fully threaded version.
When to Choose Partial Thread (DIN 931)?
A partially threaded bolt has an unthreaded plain shank section. In shear-loaded joints, this plain section keeps the load off the threads and increases the fatigue life of the connection. It is preferred in long-grip, dynamically loaded structural joints.
When to Choose Full Thread (DIN 933)?
Being threaded along its full length, a DIN 933 bolt provides full thread engagement at short grip lengths. It is the standard solution for general-purpose assemblies where the nut or tapped hole may sit anywhere along the bolt.
In summary: DIN 931 is the right choice for shear-bearing, thick-clamped joints; DIN 933 for short-grip general assembly. We manufacture both products in 8.8 and 10.9 strength grades.