DUO System – Frame Connectors


DUO-System is strategically engineered for fast processing while maintaining a design of traditional frame joint. Simple and easy-to-use. The most common applications are for Bed Rails, Stringers, and Table aprons. We recommend accessories → 2 Flute Straight Router Bit 13/32″ to be combined with —> Router Bushing 1″ OD and the MULTI F Routing Jigs to make make the mortise. Optionally, → Router Base Plate Adapter that holds the Router Bushing 1″ OD.

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DUO-System Frame Connectors

The DUO-System provides the optical qualities of traditional frame joints while being engineered in an innovative manner for fast processing and application. For example, the DUO 100/15 is an ideal frame connector for beds, and, like all KNAPP connectors, is non-visible, can be disassembled, and self-tightening. Beds made with the DUO 100/15 provide the perfect finished look with no visible fastener parts.

The DUO system is non-visible as it is installed in a mortise or rebate using our Routing Jig with a depth of 13 mm and milled either into the end-grain or face of the wood component. The DUO-System connector consists of two identical connector parts, made of high strength blue-galvanized weather-resistant steel, and is manufactured in Austria.

The choice of the correct DUO connector size depends on the used timber dimension. The milling operations can be made optionally with a hand router or a CNC. It is so quick and easy to assemble that even the end-user can do it, and with 8 different sizes, you will be sure to find the exact size you need.

Features and Benefits:
  • Fast assembly
    • Efficient and very good to use in production line manufacturing.
    • Components are simply hooked together in seconds
    • Reduces labor and equipment cost
    • Efficient: High degree of pre-manufacturing.
    • Components can be transported and simply assembled on site.
  • Non-visible connector
    • Appeals to the architect and customer
    • Concealed
  • Self-tightening
    • Adjust with the included pan head screw to desired tightness
    • Can be disassembled and reassembled
  • Versatile
    • The wood component can shrink and swell, while the joint can be adjusted and re-tightened via the screws of the fastener.
    • Safe and tested by HFA (Holzforschung Austria)
  • Perfect for industrial manufacturing with CNC
  • For handheld routers, use the Routing Jig for a perfect installation every time.
  • Used with all wood and board materials
  • Tables and chairs
  • Bed frames
  • Stairs i.e. stringer to post
  • Columns and beams
  • Booths and pews
  • Interior design
  • Small timber construction
By screwing with CS-screws Ø 5 mm or Ø 6 mm (Length as required) and PH-screws Ø 5 mm or Ø 6 mm
Concealed, self locking, by adjustable screw connector, for frame connections
With CNC-Machine, Long hole drilling machine, Hand router
Suitable materials
All solid and plywood materials from 21 mm
Frame connections for furniture, stairs and Stand construction to Interior design