An assembly comprises a platform including a first clamping surface, a track proximate to an edge of the first clamping surface, and a clamp mechanism including a second clamping surface. The clamp mechanism is configured to clamp a workpiece between the first clamping surface and the second clamping surface. The clamp mechanism is mounted to the track. The clamp mechanism is positionable at different locations along the track. The assembly may further comprise one or more adjustable spacer blocks mountable to the track to facilitate precisely positioning a workpiece proximate to the track at least two different spacings.