A wedge clamp for clamping a plurality of planar members in a side-by-side disposition for work such as gluing to be performed thereon. The wedge clamp includes a rail unit which defines a track having two opposing side walls and an end wall disposed in a U-shaped configuration to closely receive the ends of stock members. The side walls are spaced apart to define a throat for closely receiving a selected thickness of stock. A base member is provided at one end of the rail unit, a second end of the base member extending away from side walls a distance at least as great as the width of the throat. The side walls and the end wall define a series of slotted openings for receiving a wedge block. At least one spacer is used to reduce the width of the throat and accommodate close receipt of the stock material defining a thickness less than that of the throat. The spacer defines an L-shaped cross section, with the first leg defining a first thickness and the second leg defining a second thickness.