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ASSY® plus 4 A2 TRH solar A2 stainless steel partial thread with underhead thread large truss head
Special double-thread screw made of high-quality, austenitic A2 high-grade steel with large truss head fitting perfectly in the metal hole for mounting roof hooks close to edges (without pre-drilling) when installing PV systems on roof structures with soft roof insulation in outdoor areas constantly exposed to weathering.
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Ideal power transmission thanks to RW recess
- More power thanks to a larger contact surface at the bit
- More stability, one-handed working and precise positioning due to the tight-fit recess and perfect fit of the bit
Friction-fit connection of metal hook for solar collector
- Flat large truss head with shank reinforcement on the underside for perfect fit of the head in metal holes
- Head with large, precisely fitting contact surface
No settling of the solar collector due to the direct transmission of compressive forces via the double thread
No settling of the PV system in the case of long-term pressure loads due to the additional anchorage of the screw in the roof batten
Maximum mounting safety in the case of wind loads due to asymmetrical single thread
- Excellent anchorage in wood due to asymmetrical arrangement of thread flanks
- Optimal matching of drill tip and thread geometry
Precise positioning and very clean drilling due to advanced centring drill tip
- Screw mounting close to edges (like pre-drilling) in rafters due to effective centring drill tip
- Powerful and precise drilling thanks to drilling cutting edges (similar to Forstner bit)
- Precise positioning on hard surfaces without slipping thanks to centring pin
- Quick screwing thanks to gentle thread start
Stainless mounting for accessible wood connections in outdoor areas exposed to weathering
- Made of austenitic, non-magnetic and non-rusting A2 stainless steel for applications in outdoor areas exposed to weathering (utilisation class 3)
- Can be used in a rural or urban environment or in an industrial atmosphere without significant exposure to chlorides or SO2
- With anti-friction coating for easy screwing
Approved as per ETA-11/0190
- Austenitic stainless steel is characterised by a high degree of corrosion resistance against aggressive industrial air, sea air, tap water, river water, mine water and salt water, as well as woods containing tannic acid. It is resistant to acid to a certain extent and not suitable for atmospheres containing chlorine gas
- We recommend using the Würth software or corresponding design aids for planning and designing your installation. Dimensioning the ASSY screws can be carried out in the Würth timber construction software from a diameter of 5 mm
- ASSY 4, ASSYplus 4 and ASSYplus 4 VG chipboard screws are optimised for use in wood and engineered wood. For applications in plastic anchors where the load 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
- Comprehensive services are available on the ASSY® Service website www.wuerth.de/assy
| Determination of the lowest rafter height in mm when using ASSYplus 4 A2 TRH SOLAR screws for roof insulation | Insulation thickness [mm] | Batten thickness [mm] | ||||||
| Screw length in [mm] | 8x190/80 | 8x250/100 | 8x290/100 | 8x350/100 | 8x400/100 | 8x470/100 | ||
| Art. no. | 0166 288 190 | 0166 288 250 | 0166 288 290 | 0166 288 350 | 0166 288 400 | 0166 288 470 | ||
 | 107 | 40 | 40 | |||||
| 87 | 60 | 40 | ||||||
| 127 | 80 | 40 | ||||||
| 107 | 147 | 100 | 40 | |||||
| 127 | 120 | 40 | ||||||
| 107 | 140 | 40 | ||||||
| 147 | 160 | 40 | ||||||
| 127 | 180 | 40 | ||||||
| 107 | 200 | 40 | ||||||
| 137 | 220 | 40 | ||||||
| 117 | 240 | 40 | ||||||
| 97 | 260 | 40 | ||||||
| 147 | 280 | 40 | ||||||
| 127 | 300 | 40 | ||||||
| 107 | 320 | 40 | ||||||
| Note: An increased shear load must be dissipated via additional ASSY screws. | ||||||||
Approved as per ETA-11/0190
The requirements of the European Technical Approval (ETA) must be observed
- Solar screw or mounting of metal hook for solar collectors on soft over-rafter insulation
- Can be used for outdoor applications and utilisation class 3
- ASSY® screws are approved for quasi-static loads
- For optimal use of the screw, use the RW bit that fits exactly
- For longer screws it is recommended to use a screw-in aid for precise positioning in the middle of the rafter
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