Self-Piercing Screw

A self-piercing screw is a steel threaded rod with a diameter of 3.5 to 3.9 mm.

On one end it has a pointed tip that pierces a thin metal or plasterboard sheet when driven in.

The thread runs along the full length, and the head end has a cross recess. Phosphate coating protects the fastener from corrosion.

Product features

A self-piercing screw allows installation work without pre-drilling. Depending on the head type and thread, the following screw variants are distinguished:

• with a cylinder head (designated LN in Knauf’s classification) – diameter 3.5 mm, length 9-11 mm;
• with a special conical head (TN) – diameter 3.5-3.8 mm, length from 25 to 64 mm;
• with a milled countersunk head (MN) – diameter 3.9 mm, length 19-45 mm;
• with a reduced countersunk head (SN) – diameter 3.5 mm, length 30 mm;
• with a countersunk head and special thread geometry (XTN) – diameter 3.9 mm, length 23-55 mm.

Application, installation rules

The main application of self-piercing screws is building and cladding profile frames with plasterboard, where the profile wall thickness does not exceed 0.7 mm. When selecting a screw, the design features of each series are taken into account:

• TN - for installing plasterboard panels (GKL, GKLV, GKLVO) to a metal frame;
• LN - for connecting metal profiles to each other;
• MN – for fastening Knauf super sheets (GVL and GVLV) to profiles;
• SN – for fixing acoustic panels;
• XTN - for cladding the frame with GSP sheets (Sapphire).

Special bits for self-tapping screws are used to drive in self-piercing screws. The screw axis is positioned perpendicular to the base, and the driver’s trigger is pressed gently, in several steps – this allows the screw to pierce the material without stripping the thread.