Abstract: Particle separating apparatus includes a horizontally disposed rectangular screen or grid having openings adapted to pass smaller particles from a stream of particles of varying sizes while retaining larger particles upon the top of the screen. A conveying screw mounted in a trough below the screen conveys the smaller particles forwardly along the trough to a discharge opening. The screen is mounted above the screw for horizontal reciprocation along a path parallel to the longitudinal axis of the screw and is biassed by springs engaged between the front and rear ends of the screen and stationary surfaces to a normal rest position midway between the ends of the reciprocating path.