Tornillo TB Punta de Broca

The Knauf TB Drill-Point Screw is a self-drilling fastener designed to secure gypsum board to metal studs whose thickness exceeds the typical range of conventional light-gauge structures.

Knauf specifically recommends its use on profiles with thicknesses:

This is precisely the key difference compared to the Knauf TN Screw. The TN uses a standard tip and is designed for metal profiles up to 0.7 mm; when the sheet exceeds that thickness, the TB’s drill point drills through the steel before the thread secures the fastener.

The result is direct panel-to-metal fastening without the need to pre-drill a hole in the profile when working within the thickness ranges defined by Knauf.

The combination of the steel’s hardness, the thread geometry, and the self-drilling tip allows the screw to penetrate the metal sheet and subsequently create a mechanical bond between the panel and the structure.

It should not be confused with the LB screw, even though both feature a drill tip. The LB is a metal-to-metal screw used to join metal elements together; the TB is designed as a board-to-metal screw for fastening gypsum board to metal studs.

Knauf establishes a fundamental rule for selecting the correct length:

Therefore, the length should not be selected based solely on the thickness of the board. There must be sufficient length to completely pass through the cladding and ensure that minimum penetration of 10 mm into the structure.

For a panel of:

In a 2 × 12.5 mm system, Knauf specifies:

In these configurations, TB lengths of 45, 55, or 70 mm are technically required in some layers. However, the current product sheet itself notes that certain lengths are not sold by Knauf Spain.

Therefore, for the commercial catalog, it is important to distinguish between the sizes technically supported by the system and the variants that Knauf currently sells in Spain.

Knauf’s official Spanish website currently lists:

For panel configurations requiring a longer length, consult the complete Knauf solution and the availability of the prescribed fastener, rather than automatically substituting it with a different screw.

The head should be slightly recessed into the surface to allow for subsequent application of joint compound, but without excessively damaging the cardboard backing of the board.

A screw that is too shallow will leave the head protruding and interfere with the finish. If it is driven in too deeply, the paper facing may be damaged, reducing the quality of the fastening.

The correct choice can be summarized as follows:

The screws used for fastening laminated gypsum boards bear the corresponding CE marking in accordance with UNE-EN 14566, the harmonized standard for mechanical fasteners intended for gypsum board systems.

Current variants: