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B&Q£3.78Visit shop B&Q - Double-Countersunk Zinc-Plated Carbon Steel Screw (Dia)4mm (L)25mmPack Of 100
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This pack of 100 Diall Double-Countersunk Zinc-Plated Carbon Steel Screws is designed for DIY enthusiasts and general construction tasks, offering a reliable fastening solution for wood and plasterboard applications. Their zinc-plated carbon steel construction ensures durability, while the double-countersunk head allows for a flush finish. A potential caveat is the need for pre-drilling, especially in harder materials, to ensure optimal performance and prevent wood splitting. Key features include their 25mm length, 4mm diameter, fully threaded design, and resistance to corrosion.
| Colour | Silver |
|---|---|
| Brand | Diall |
These screws typically feature a cross-head (Phillips or Pozidriv) recess. Ensure you use the correct bit size and type for a secure fit and to prevent stripping the head.
The zinc plating offers some corrosion resistance, making them suitable for sheltered outdoor applications. However, for prolonged exposure to moisture or harsh weather, stainless steel or specially coated exterior screws are recommended.
No, these screws are designed for general DIY and light to medium-duty tasks, not for structural load-bearing applications. Always use screws specifically rated for structural work when needed.
A single-countersunk screw has a conical underside to its head that sits flush in a similarly shaped hole. A double-countersunk screw has this feature and an additional flat underside to the head, allowing it to sit flush even in materials where the hole is not perfectly countersunk or is a simple clearance hole.
For wood, pre-drill to the depth you intend to drive the screw. For plasterboard, pre-drilling helps guide the screw straight; the depth is less critical as the plasterboard material itself provides purchase.
The screws are constructed from durable carbon steel with a zinc-plated finish for added corrosion resistance.
Ensure you are using the correct screwdriver bit type and size. Apply firm, consistent pressure. If using a drill, set it to a lower torque setting or use a clutch setting to prevent overtightening.
Check if the pilot hole is too large or if the material is too soft. For plasterboard, ensure you are screwing into the board itself, not just into a void. Consider using wall anchors if fixing to plasterboard is proving insufficient for the load.
This indicates the pilot hole was likely too small or omitted entirely. Always pre-drill a pilot hole in wood, especially near edges, with a diameter smaller than the screw's core.
Ensure the countersinking is adequate. You may need to slightly enlarge the top of the pilot hole with a slightly larger drill bit or a countersink bit to allow the screw head to sit flush.
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