SPAX window construction screw FEX-A WIROX - coarse thread, countersunk head, cross‑recess, drill point

Spax window‑construction screw FEX‑A WIROX - Features

Compared with the simple slotted power drive, the cross‑slot power drive has the advantage that the screwdriver no longer slips out sideways and thus cannot damage the workpiece. We integrate the cross‑slot H power drive in our window‑construction screws (FEX) and drywall screws (GIX), as the required screwing torque in these applications is not so high.

The countersunk head (or flat countersunk head) mills a recess into the wood with its polygonal underside (“pockets”) and can therefore be sunk without additional countersinking of the screw hole. The countersunk head sits flush with the surface.

Screws with coarse threads form their mating thread in the wood themselves. Unlike sheet‑metal screws with fine threads, power transmission in coarse‑thread screws takes place over the entire thread length, which allows the thread turns to be spaced further apart. Our rapid‑assembly screws GIX B also have a coarse thread and are used for timber studwork.

In certain areas you need to fasten wooden attachments to metal substructures. This is the case, for example, with our terrace screw SPAX ALU or in drywall construction. Since normal screws would fail on hard metal, we also offer screws with a special drill tip. Externally it resembles the tip of a metal drill bit and has two small cutting edges. The SPAX ALU pre‑drills in aluminium up to 4 mm wall thickness so that the thread can cut into the material. You can drive it in just as easily as our wood‑construction screws.

What this means for you: For metal wall thicknesses of 2 mm and aluminium of 4 mm, the usual pre‑drilling with a metal drill is unnecessary. No bit changes, no broken thin metal drill bits in the screw hole.

With WIROX, SPAX has developed a coating that is far superior to galvanisation in terms of corrosion protection. WIROX uses no chromium(VI); the screws remain just as durable even after years in outdoor areas not directly exposed to the elements, and are also environmentally friendly. WIROX screws are the first choice for all open structures without direct weather exposure, such as carports or pergolas; for direct weathering stresses, such as on terraces, we recommend our screws in the stainless steel variant.