STAINLESS STEEL WOOD SCREWS FOR HARDWOOD WITH CONCEALED CYLINDRICAL HEAD KKZ A2 | AISI304
Stainless steel outdoor wood screws for hardwood: concealed head and spear-point tip KKZ A2 AISI304
The KKZ A2 | AISI304 stainless steel wood screws for hardwood are designed for fastening wooden boards outdoors in aggressive environments. The special spear-point tip allows very high-density wood species up to 780 kg/m³ to be screwed without pre-drilling, and woods up to 1240 kg/m³ with pre-drilling — including exotic woods such as IPE, massaranduba and LVL bamboo over 1000 kg/m³.
The concealed cylindrical head guarantees a clean and invisible aesthetic finish on the surface of the timber, ideal for terrace flooring and façade cladding. Available in the standard version and in the KKZ BRONZE A2 | AISI304 bronzed version in an antiqued colour, perfect for blending in with darker wood species.
Made from A2 | AISI304 (CRC II) austenitic stainless steel, the screw is suitable for service classes SC1, SC2 and SC3 and for environments with atmospheric corrosivity up to C4. It is also resistant to acidic woods with pH below 4 such as oak, Douglas fir and chestnut.
KKZ A2 AISI304: double thread and spear-point tip for fastening on very high-density woods
KKZ A2 | AISI304 screws for hardwoods without pre-drilling are available in 5 mm diameter and lengths of 50, 60 and 70 mm, with CE certification according to EN 14592. The large-diameter right-hand underhead thread ensures effective tensile resistance, guaranteeing the correct coupling of the wooden elements: the characteristic thread withdrawal values reach up to 3.17 kN for the L70 version.
The spear-point tip drastically reduces insertion forces on very high-density woods, eliminating the need for pre-drilling on densities below 780 kg/m³ and allowing use with pre-drilling on species such as IPE and massaranduba over 1000 kg/m³. The minimum edge distances comply with EN 1995:2014, with spacings suitable for installations both with and without pre-drilling.
A2 | AISI304 stainless steel guarantees resistance to wood corrosion up to class T4, making it suitable also on aggressive woods with pH below 4. The TX25 bit is included in the box, allowing immediate installation without additional tools. The KKZ outdoor wood screws are also compatible with WPC boards with pre-drilling.
Can stainless steel screws be used in exotic woods such as IPE or massaranduba without pre-drilling?
On woods with density below 780 kg/m³, the KKZ A2 | AISI304 is installed without pre-drilling thanks to the spear-point tip. For very high-density species such as IPE, massaranduba and LVL bamboo (over 1000 kg/m³), pre-drilling with a diameter of 3.5 mm is required.
The spear-point geometry of the tip is designed to minimise insertion forces on hardwoods, avoiding splits and guaranteeing precise fastening even on the most difficult species. AISI304 steel is suitable on acidic woods (pH<4) such as oak and chestnut without risk of accelerated corrosion. The KKZB bronzed version is recommended for use on horizontally-laid boards (terraces).
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KKZ A2 | AISI304
