4mm Spax Wirox Universal Countersunk Screws - Partial Thread

• Application: Universal usage
• No pre-drilling (wood-dependent)
• Quick and safe fastening with reduced driving in torque (more screwed connections per battery charge)
• Effectively reduces splitting of the wooden material, even when close to the edge
• Requires T-Star Plus T-20 Driver

Spax created T-STAR plus driver – is a so-called hexalobular internal. Compared to less precise-fitting drive types like Phillips or cross recess, the contact surface is many times larger with the T-STAR plus, and the T-STAR plus bits are always positioned optimally in the screw head. The maximum, precise force transmission from the screwdriver to the screw that results from the use of T-STAR plus thus enables simple and ultra-fast work with much more efficiency than with other drives. What this means for you: No more annoying bit slips from the screw head – you can take care of serial fastening in no time at all!

The countersunk head (or flat countersunk head) is the most common head geometry in the world of SPAX. It has a conical shape and, in the case of SPAX, is characterised by the 90° MULTI head. The countersunk head screws offer the ideal compromise between maximum resistance to tightening torques and a discreet and attractive screw connection. With its polygonal underside ("pockets"), the flat countersunk head mills its own way into the wood and can therefore be countersunk into the wood cleanly and flush without having to pre-drill the screw hole. What this means for you: Flush screw insertion becomes child's play – with no need to pre-drill or countersink the screw hole.

In principle, all of Spax's screws can be organised into two groups: screws with partial thread and screws with full thread. Screws with partial thread are ideal for fastening components like engineered wood boards, panels, floorboards and even squared timbers on load-bearing components like stud framing or posts. While the thread makes its way through the load-bearing component, the thread-free shank of the partial thread screw should pull all the way through the top attachment. When the screw is inserted further, the screw head pulls the upper component onto the lower one. By inserting the screw, maximum contact pressure is therefore created between the two components. Of course, this effect is ideal when the thread-free shank has at least the same thickness as the attachment. What this means for you: Partial thread screws offer the ultimate clamping force in wood construction.

The term 4CUT is used to describe the fact that the point of Spax screws are not rounded, but rather shaped like an arrow. These four edges displace the wood fibres upon insertion and thus create space for the core diameter of the screw. The otherwise inevitable expansion at the core of the wood is effectively reduced, minimising wood splitting around the edges. The required cordless screwdriver torque is also reduced, since the screw core no longer needs to "squeeze" into the wood. What this means for you: Practically no pre-drilling required any longer – even in the edge areas of your workpiece that are normally prone to splitting! The 4CUT means you can skip an entire work step.

Effective corrosion protection is a must for screws used for outdoor structures not exposed to the elements. For this, SPAX has developed the WIROX coating, which far outdoes conventional galvanisation in terms of both protection and durability. The WIROX-coated screws are significantly more resistant to mechanical stress than their counterparts with chromate conversion coating. No chromium(VI) is used for WIROX, which means that even after years in an area not directly exposed to the elements, the screws are not only just as resilient, but are entirely environmentally friendly, too. Spax's WIROX screws are the ideal choice for all open structures without direct exposure to the elements, such as carports and pergolas. For areas with extreme weather exposure, such as decking, we continue to recommend Spax's stainless-steel screws. What this means for you: When you use Spax's corrosion-protected screws outdoors, you can be safe in the knowledge that your structure is well fastened – in outdoor areas not directly exposed to the elements, WIROX keeps our screws statically rigid and reliably protected over many years. So there's no need for visual inspections every year!