Wood screws for joints with a countersunk head
Countersunk TX wood screws are intended for fastening components to a wooden substrate. The countersunk head allows the screw head to sit within the attached component. Selection depends on the material and thickness of the components, the required engagement in the wood, joint loading and the service environment.
The size overview on this page is based on the WKCS range by Klimas Wkręt-met in the yellow zinc-plated and waxed configuration. It covers specific diameter and length combinations from 3 to 10 mm diameter listed in the manufacturer's catalogue.
Head, drive and thread
- Countersunk head
- The conical bearing surface allows the head to be recessed into the component. The final seating depends on joint preparation and material properties.
- TX drive
- The internal six-lobe drive transfers torque from the bit to the screw. The WKCS bit size varies with diameter from TX10 to TX40; the table gives the exact pairing.
- Wood screw thread
- WKCS has a partial thread and an unthreaded shank section. Thread length depends on screw size; sizes are written as diameter × overall length.
- Manufacturer and range
- Klimas Wkręt-met, WKCS.
Material
WKCS material: carbon steel. This is specified in the manufacturer's technical data sheet. Zinc plating and the wax coating are separate surface treatments applied to the base material.
Surface finish: yellow zinc plating + wax coating
Zinc plating
Zinc forms a protective surface layer. Yellow zinc plating does not identify a stainless steel material; the environment in which the joint will operate must be considered during selection.
Wax coating
Wax acts as a lubricating layer to reduce friction during driving. Installation must still follow the instructions for the particular configuration and substrate.
For outdoor or persistently damp environments, the suitability of the specific finish must be assessed against the product documentation and service conditions.
WKCS diameters and lengths
The table lists individual lengths of yellow zinc-plated WKCS screws from the Klimas catalogue. It does not imply that every intermediate length is manufactured. The manufacturer's technical data sheet marks lengths of 440, 480, 520, 560 and 600 mm at 8 and 10 mm diameter as products available to order.
| Diameter (mm) | Lengths (mm) | TX drive | Designation |
|---|---|---|---|
| 3 | 30, 35, 40 | TX10 | WKCS |
| 3.5 | 30, 35, 40, 50 | TX15 | WKCS |
| 4 | 30, 35, 40, 45, 50, 60, 70 | TX20 | WKCS |
| 4.5 | 40, 50, 60, 70, 80 | TX20 | WKCS |
| 5 | 40, 50, 60, 70, 80, 90, 100, 120 | TX25 | WKCS |
| 6 | 50, 60, 70, 80, 90, 100, 120, 140, 160, 180, 200, 220, 240, 260, 280, 300 | TX30 | WKCS |
| 8 | 80, 100, 120, 140, 160, 180, 200, 220, 240, 260, 280, 300, 320, 340, 360, 380, 400, 440, 480, 520, 560, 600 | TX40 | WKCS |
| 10 | 120, 140, 160, 180, 200, 220, 240, 260, 280, 300, 320, 340, 360, 380, 400, 440, 480, 520, 560, 600 | TX40 | WKCS |
The size overview is for reference and does not represent current JENPEX stock. Availability of a specific size and configuration will be confirmed upon enquiry.
Measuring WKCS length: the manufacturer's drawing defines Lw as the overall length including the head, from the tip to the top face of the countersunk head. Thread length Lg is a separate dimension and varies with screw size.
Selection for the application
The manufacturer specifies WKCS for structural connections between wooden members. Listed substrates include solid timber, glued timber members and laminated veneer lumber (LVL); applications include roof-framing joints and timber structural frames. The specific size must be selected according to the joint design, substrate, loading and the conditions in the applicable documentation.
The manufacturer publishes European Technical Assessment ETA-18/0817 for the WKCS range. Use in a load-bearing joint must comply with its conditions and the joint design.
Installation and replacement of an existing screw
Use a bit matching the drive of the specific screw size. The need for pre-drilling, preparation of the countersink and the installation procedure depend on the manufacturer's instructions, the substrate material and the joint arrangement.
When replacing a screw, compare the size, head, drive, thread and required finish. Matching diameter and length alone do not guarantee interchangeability.
Design features of the WKCS range
The WKCS technical data sheet describes underhead cutting ribs, a milling tip, cutting notches on the thread, an additional thread at the tip and shank ribs. These features assist initial engagement, cutting of wood fibres and reduction of driving resistance. Refer to the drawing of the selected size when specifying the screw.
Related categories
Looking for a specific wood screw size?
Send us the required diameter, length and quantity. When replacing an existing screw, include its designation, a photo or a technical datasheet. We will check availability and a suitable configuration.
Request a quote →