Both self drilling screws and self tapping screws belong to self tapping fasteners. Although they both have self tapping locking function, there are significant differences in the four core specifications of head type, hole type, tooth type, and drill tail, which directly determine their applicable scenarios and installation methods.  

    In terms of head shape:

    common types of self drilling screws and self tapping screws include: PAN HEAD,OVAL HEAD,HEXAGONA WAFER HEAD,CSK HEAD,LARGE WAFER HEAD,PAN CAKE HEAD,BUGLE HEAD,PAN FRAMING HEAD,HINGE HEAD,WAFER HEAD,TRUSS HEAD. Self tapping screws are commonly used for aesthetic and convenient installation, suitable for light load scenarios such as furniture and household appliances; The types of self drilling screw heads are mostly hexagonal heads, hexagonal flange heads, and pan heads, which meet the requirements of the national standard GB15856 series. The hexagonal head can withstand higher torque and is suitable for heavy-duty scenarios such as steel structures. The flange head can increase the contact area and prevent loosening.

On the hole:

common ones include PHILLIPS, SQUARE, HEXAGONA,The self tapping screw does not have a built-in drilling structure and must be pre drilled with a suitable hole diameter (about 0.8 times the diameter of the screw) on the substrate, otherwise it cannot be penetrated; The self drilling screw comes with its own drill tail and does not require pre drilled holes. It can be directly drilled, tapped, and locked in one step, greatly improving construction efficiency.

In terms of tooth types:

common ones include: 6 # -20T, 7 # -19T, 8 # -18T, 10 # -16T, 12 # -14T, 14 # -14T, 10 # -12T, 12 # -11T, 14 # -10T, etc. Among them, self tapping screws have finer tooth types and even pitch, divided into coarse teeth and fine teeth. Coarse teeth are suitable for soft substrates such as wood and plastic, while fine teeth are suitable for thin metal plates and rely on thread extrusion to form bite; The self drilling screw has a thicker tooth profile, slightly larger pitch, and thread specifications ranging from ST2.9 to ST6.3. It has stronger toughness and retention, and is suitable for hard substrates such as metals, making it more firmly engaged.

Drill tail, common ones include:

TYPE 17,TAPPING,SPOON,WING TEKS,PT.1,PT.2,PT.3,PT.4,PT.5,PT.6

The tail of the self tapping screw is pointed or flat, without drilling structure, and can only rely on thread tapping; The tail of the drill screw is equipped with a drill bit like tail, which has a double cutting edge or three cutting edge structure and can quickly penetrate thin steel plates, color steel plates, etc. According to the hardness of the substrate, it is divided into pointed tail, round tail and other types, suitable for substrates of different thicknesses and hardness.