DUO System – Sample Pack

The DUO System Sample Pack includes three frame connector samples designed for strong, precise, and hidden frame connections in furniture, staircases, and timber construction. Each connector provides the traditional look of a mortise-and-tenon joint while offering the speed and flexibility of a modern fastening system.

Included in the pack:

• 1 × DUO 46/30

• 1 × DUO 62/15

• 1 × DUO 90/20

Each DUO connector is made of two identical blue-galvanized steel plates that hook together in a dovetail-like manner. Once installed, the joint is self-tightening, adjustable, and concealed within the mortise for a clean, professional appearance. The system can be installed using a router, long-hole drilling machine, or CNC, and can be disassembled and reassembled as needed.

Features and Benefits

• Fast and efficient assembly suitable for production or workshop use

• Concealed connection for a clean, seamless finish

• Adjustable, self-tightening design with fine-tuning screws

• Reusable and re-tightenable connection

• Tested for safety and load capacity by Holzforschung Austria

• Works with both manual and CNC routing

• Made from durable, weather-resistant zinc-coated steel

• Tables and chairs

• Bed frames and furniture

• Stair stringers and posts

• Columns, beams, and booths

• Interior joinery and small timber structures

• Quantity included: 3 connectors (1 each of DUO 46/30, DUO 62/15, DUO 90/20)

• Material: Blue-galvanized weather-resistant steel

• Coating: Zinc-plated for corrosion resistance

• Connector type: Self-locking hook connector for frame joints

• Mounting: Screw with CS or PH screws Ø 5 mm or Ø 6 mm (length as required)

• Advantages: Concealed, self-locking, adjustable connector for frame assembly

• Suitable materials: All solid wood and plywood materials 21 mm and thicker

• Recommended accessories:

  • KNAPP Routing Jig

  • Ø 15 × 25 mm TCT Slotting Cutter

  • CS screws 5×40, 5×60, 6×40, or 6×60 mm (per Ö-Norm M5027)

• What is included: Three DUO System connector samples (one of each type listed)

Load Values (Transverse Force, F₀):

• DUO 46/30 → 1.30 kN

• DUO 62/15 → 1.29 kN

• DUO 90/20 → 2.37 kN

Values based on Holzforschung Austria certificate from 2000.

Steps

1. Cut the mortise using the KNAPP Routing Jig to align both components, routing 13 mm deep with a Ø 15 × 25 mm TCT Slotting Cutter.

2. Insert the first connector plate into the mortise and predrill the screw holes.

3. Attach the first DUO plate using CS or PH screws.

4. Place the second plate over the first and install the pan head screws until snug to ensure the correct depth and fit.

5. Secure the second connector plate to the matching component.

6. Hook the parts together and tap gently with a rubber mallet until locked in place.

Tips

• For CNC routing, program the mortise at 13 mm deep using a Ø 15 × 25 mm TCT Slotting Cutter.

• The joint stays tight and allows for wood movement.

• Adjust the screws as needed to fine-tune the connection.