Indented hexagon head with collar hi lo thread screws

a) Unlike DIN 912, DIN 7984 screws features a low-profile head and a hexagonal socket drive (Socket thin head cap screws) with metric thread ranging from size M3 to M24

b) DIN 7984 screws have a thinner head because they are designed to be countersunk, allowing them to sit flush with the material surface. However, this design may not provide the same torque transfer capacity as the thicker head of DIN 912 screws, which are designed to handle higher torque due to their thicker cylindrical head shape.

Extremely low head

Nylok blue patch

a) A weld screw is a fastener specifically designed for welding onto metal surfaces, particularly steel. It is coated with a thin layer of copper, which enhances conductivity and improves weld quality by ensuring a strong and consistent bond.

a) A ribbed neck screw is a type of fastener designed with a special feature on its shank or neck. Instead of a smooth or threaded surface, the neck of the screw has ribbed, serrated, or knurled features. These ribs or serrations provide additional grip and resistance when the screw is driven into a material, preventing it from rotating or loosening.