Tools

 

To avoid damage to the head of the fastener or coating, sockets should be well-fitting and in good condition, and drive bits should be the correct size (2 or 3) and type Phillips, Pozidrive or square drive.

When drilling 3 mm steel the actual drilling takes seven seconds, but the threading takes less than one second, so the reaction is immediate and should be automatic to avoid damaging the roof cladding.

When drilling thick steel, elongated drill points are necessary to avoid breaking the screw. Alternatively, a self-threading screw can be used with a pre-drilled hole suitable for the gauge and thread of the screw.

When fasteners are used to secure to a metal less than 0.9 mm thick strip-out can occur if the screw is driven at too fast a speed, even at a low torque setting.