KNAPP‑Dowel 8 x 50 mm – Plastic Self‑Tightening Dowel

The KNAPP-Dowel 8×50 mm is the largest and strongest option in the KNAPP-Dowel family, designed for heavy-duty joinery and demanding applications. Its extended length provides maximum holding power, making it ideal for load-bearing connections in windows, doors, exterior furniture, and marine millwork.

Made of high-strength, weather-resistant POM plastic, the 8×50 mm dowel won’t shrink, swell, or rot, even under extreme humidity or outdoor conditions. The threaded ribs and lengthwise grooves anchor firmly in the borehole, creating an immediately load-bearing joint without clamps.

For permanent and structural applications, pair with KNAPP-Adhesive PU+ (Z011/1). The grooves and holes allow optimal glue distribution, ensuring long-lasting stability even in challenging environments.

Features and Benefits

• Largest 8×50 mm size – engineered for maximum strength and stability

• Extended length provides superior load-bearing capacity

• Weather- and UV-resistant POM plastic for outdoor use

• Immediately load-bearing – no clamping required

• Stronger alternative to traditional wooden dowels; won’t swell, shrink, or rot

• Ideal for exterior and high-humidity joinery

• Windows and doors

• Outdoor furniture

• Architectural millwork

• Boat and marine joinery

• Heavy-duty cabinetry and case goods

• Shopfitting projects requiring extra holding strength

• Size: 8×50 mm

• Material: Polyacetal (POM), weather-resistant plastic

• Mounting: Knock-in; optional gluing with KNAPP-Adhesive PU+

• Installation: Works with doweling jigs, joiners, and automated dowel insertion machines

• Advantages: Concealed, self-tightening, heavy-duty dowel; immediately load-bearing

• Suitable Materials: Solid wood, plywood, MDF, HDF, and composite materials

Steps

1. Predrill boreholes (8–8.2 mm diameter recommended for insertion machines).

2. Optional: Apply KNAPP-Adhesive PU+ (Z011/1) into the borehole for a permanent bond.

3. Insert the dowel using a dowel insertion machine or hammer in by hand.

4. Assemble the workpiece with a rubber mallet.

Tips

• Slightly undersized boreholes give the best holding power.

• Oval grooves ensure the dowel applies pressure in the lengthwise direction, reducing stress on edges.

• Threaded ribs allow dowels to be removed or adjusted.

• Recommended borehole depth: approx. 55 mm.

• For CNC machining: chamfer melamine/laminate holes 0.5–1 mm.