Wedge

Wedge

Definition

A Wedge refers to a small, tapered insert-often made of wood or metal-used in frame joinery to reinforce mitered or butt joints. In picture framing, it is commonly associated with v-nails, biscuits, or dovetail keys that are driven or pressed into pre-cut slots at the corners of a frame to ensure structural stability.

Function in Joinery

• Provides mechanical strength by locking two moulding rails tightly together.
• Often used in conjunction with adhesive or glue for added reinforcement.
• Can be inserted from the back of the frame (as with V-nails) or through a routed slot (as with spline or dovetail keys).

Types of Wedges

• V-Nails / Underpinner Wedges - Metal wedges driven into the back of a frame using an underpinner.
• Thumbnail or Biscuit Wedges - Oval or key-shaped inserts placed into routed slots on the moulding.
• Dovetail Keys - Decorative or functional wood splines visible from the side or face of the corner.

Related Terms

• Frame Chop
• Spline Joint
• Miter Joint
• Bridle Joint