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ASSY® 4 COMBI timber screw Steel zinc plated partial thread hexagon head
Powerful partial-thread screw with shank reinforcement for wood-wood fastening with washer or precise 90° metal-wood fastening in wood construction in indoor dry or sheltered areas
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Ideal power transmission thanks to RW drive
- More power due to larger contact area at the bit
- More stability, one-handed working, precise positioning due to the tight-fit recess and perfect fit of the bit
- Fewer bit changes, one bit for many screw diameters
- Compatibility with previous AW drive
Precise fit in metal and very high power transmission combined with two drive types
- Shank reinforcement integrated on the underside
- Combination of hexagon and RW drive
Significant reduction in the amount of force required when fastening in the screw
- Less splitting when immersing the shank due to the displacement milling effect of the milling shank
- Minimised risk of screw breakage due to high breaking torque
- Reduced risk of injury from protruding metal chips due to the integration of the milling shank into the thread
- High protection of the application tools
No over-tightening or stripping and high feed
- Higher power transmission in hardwoods due to reinforced, asymmetrical thread flank geometry of the coarse thread
- Better anchoring thanks to higher thread flanks
Smooth thread start ensures optimised recessing and biting of the screw
- Reduced splitting effect due to displacement effect of the dome-shaped milling elements in the tip
- Friction-reduced thread rotation allows reduction of the screw-in force to be applied
High strength values and ductility
- Adjusted heat treatment guarantees high strength values and high ductility
- We recommend using the Würth software or the corresponding design aids for planning and dimensioning your assembly. Use the Würth timber construction software for dimensioning of ASSY screws from a diameter of 5 mm
- Do not use the screw in applications with direct exposure to the elements or in humid rooms with atmospheres containing chlorine gas. If used outdoors and in rooms that are constantly exposed to high humidity, please use ASSY 4 A2 combi stainless steel screws
- ASSY 4, ASSYplus 4 and ASSYplus 4 FT chipboard screws are optimised for use in wood and wood materials. For applications in plastic anchors where load capacity can also be reduced, use only screws without an optimised thread tip (tip with milling ribs, drill tip, self-clearing groove etc.), such as the ASSY D screws with countersunk head or pan head
For wood-wood connections designed to pull together
The partial thread starting immediately below the shank allows for wood-wood connections designed to pull together. The screw thread is positioned entirely in the lower component once screwed in.
For applications in utilisation class 1 and utilisation class 2 (from ∅ > 4 mm)
- High-quality surface protection, zinc, blue-passivated chromium(VI)-free 8 µm layer thickness
- Suitable for use in utilisation class 1 (interior) and from a ∅ > 4 mm in utilisation class 2 (covered outdoor area) according to EN 1995-1-1:2010-12 + DIN SPEC 1052-100:2013-08
- The requirement of classification T2/C2 is fulfilled in accordance with prEN 14592:2017 (D)
- ASSY screws are approved for quasi-static loads
- For optimum use of the screw, the right-size RW bit must be used
- For cylindrical 90° holes in the metal tab to be fastened, it is recommended to use ASSY screws with shank reinforcement (ASSY 4 Combi, ASSY plus FT 4 combi, ASSY 4 JH joist hanger screw). The gap between the hole and the screw shank should not exceed 1 mm in accordance with DIN EN 1993-1-8
- For a load-bearing wood-metal connection, ASSY screws must be tightened to a specific torque value. Tightening torque = required prevailing torque x 1.2 < 90% of the breaking torque
- To increase the joining effect or head pull-through resistance, combining with perfectly fitting washers for ASSY 4 is recommended
- Partial-thread screws are ideal for connecting wooden components. To achieve optimum assembly of the components, the components to be fixed must not be thicker than the length of the shank
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