Koelner/Rawlplug construction screws 4.0x35 mm are metal fasteners with a partial thread and a countersunk (conical) head designed to sit flush with the surface after installation. Supplied in a pack of 26 pieces, these screws are intended for joining wood-to-wood or wood-to-metal elements in structural joinery, framing, furniture assembly and general building repairs where a recessed head and secure clamping are required.
Advantages
The partial thread combines strong clamping force with controlled penetration, drawing the two components tightly together while reducing the risk of over-threading in thin elements. The countersunk head creates a flush finish suitable for visible surfaces or for subsequent covering with filler or caps. Manufactured to suit common pilot-drilling and driver bits, these screws provide consistent seating and repeatable performance in typical construction materials.
Suitable for
- Structural timber joints and framing
- Furniture assembly where a flush head is needed
- Attaching wooden components to light metal profiles
- General building repairs and renovation work
When it may not be suitable
These screws are intended for applications where a partial thread and a countersunk head are appropriate. They are not suitable for situations that require full-thread fasteners for maximum withdrawal resistance along the entire shaft, or where a non-recessed head (pan, hex, or washer head) is specifically required for the joint design. They may also be less suitable for use in very hard or excessively thin materials without correct pilot holes.
Key specifications
- Diameter: 4.0 mm
- Length: 35 mm
- Thread type: partial (incomplete) thread
- Head type: countersunk (conical) head for flush seating
- Material: metal (steel or similar, intended for typical construction use)
- Pack quantity: 26 pieces
How to use
Select an appropriate pilot hole size for the 4.0 mm nominal diameter and the material being fastened; pilot-drilling helps prevent splitting in hardwoods and ensures proper seating. Place the screw so the countersunk head aligns with the surface, then drive with a compatible driver or bit at controlled speed until the head is flush or slightly recessed. For wood-to-metal connections, ensure the metal profile is suitable for tapping or use a clearance hole followed by engagement in the underlying timber. Do not overtighten; stop when the head is flush and the joint feels secure.
What to consider before purchase
- Confirm that a 4.0 x 35 mm screw length and partial thread meet the requirements of your joint.
- Check material compatibility (type of wood or metal profile) and whether corrosion resistance is needed for your application.
- Ensure you have the correct pilot-drill size and driver bit for the screw head profile.
Usage recommendations
For reliable results, pre-drill pilot holes in hardwoods and use consistent torque when driving countersunk screws to avoid recessing the head too deeply. When appearance matters, countersink slightly deeper and fill as needed for a smooth finish. Store screws in a dry place to maintain condition.
