DUO 30 + DUO 35 – Sample Pack

The DUO 30 / DUO 35 Sample Pack includes eight pairs of precision steel hook connectors engineered for fast, concealed, and adjustable assembly. These connectors consist of two identical round-shaped brackets that hook into each other in a dovetail-like manner, forming an immediately load-bearing and self-tightening joint once screwed and connected.

Each pack contains:

• 2 × DUO 30 oL (no lateral tolerance)

• 2 × DUO 30 mL (with 1.7 mm side tolerance)

• 2 × DUO 35 oL (no lateral tolerance)

• 2 × DUO 35 mL (with 1.7 mm side tolerance)

The DUO 30 and 35 install easily using the KNAPP Forstner Bit with adjustable depth stop. Their compact 3 mm recess depth makes them ideal for tight, aesthetic connections in furniture, wall panels, stair treads, and millwork. The oL versions ensure a rigid fit, while the mL versions provide slight lateral movement for easy alignment during installation.

Features and Benefits

• Fast assembly – components hook together in seconds

• Concealed connection with no visible hardware

• Self-tightening design for secure, load-bearing joints

• Adjustable tolerance (mL = movable / oL = fixed)

• Can be disassembled or permanently locked with an optional clip

• Minimal recess depth (3 mm) for slim designs

• Compatible with standard CS or Euro screws

• Wall and ceiling panels

• Stair treads and handrails

• Doors and windows

• Furniture and architectural millwork

• Shopfitting and interior fixtures

• Quantity included: 8 pairs (16 pieces total)

• Material: Steel – zinc plated

• Coating: DUO mL = blue galvanized; DUO oL = yellow galvanized

• Connector type: Hook-in connector system

• Mounting: Screw-in with CS screws (3×13 mm or 3.5×16 mm for DUO 30) and Euro-screws (6×10 mm for DUO 35)

• Advantages: Concealed, self-tightening, demountable connection with optional locking clip

• Suitable materials: All wood and board materials

• Recommended accessories:
  – KNAPP Forstner Bit Ø 30 mm or Ø 35 mm with adjustable depth stop
  – DUO Center Punch for precise alignment
  – Locking Clip (for DUO 30 permanent connections)

• What is included: Eight connector pairs (2 each of DUO 30 oL, DUO 30 mL, DUO 35 oL, DUO 35 mL)

Steps

1. Mark placement using the KNAPP Drilling Jig or template.

2. Drill recess with the KNAPP Forstner Bit (Ø 30 mm for DUO 30 or Ø 35 mm for DUO 35) to a depth of 3 mm.

3. Transfer position using the DUO Center Punch to mark the matching surface.

4. Secure connectors on each component using the recommended screws for the material type.

5. Hook the parts together until fully engaged in the dovetail fit.

6. Tap gently with a rubber mallet to seat the connection securely.

Tips

• Use the Drilling Jig for accurate hole placement every time.

• The adjustable depth stop on the Forstner Bit ensures consistent 3 mm depth.

• DUO mL versions allow slight sideways movement (± 1.7 mm); DUO oL versions do not.

• Use the optional Locking Clip with DUO 30 to create a permanent joint.