Material returning device

The utility model discloses a material returning device which comprises a material returning piece and a fixing support. The lower end of the screw rod returning piece is connected with the screw rod fixing support, a through hole through which a core rod on the chuck can penetrate is formed in the upper end of the screw rod returning piece, the screw rod through hole is aligned to the core rod, a workpiece is fastened at one end, penetrating through the through hole, of the core rod, and the aperture of the screw rod through hole is smaller than the diameter of the end face of the workpiece; and during material returning, the chuck retreats to drive the core rod and the workpiece to retreat, when the end face of the workpiece touches the side face of the material returning piece, the workpiece is jacked, the core rod continues to retreat to the initial position, and the workpiece is jacked out of the core rod by the material returning piece. Even if the inner hole of the workpiece has a tolerance lower limit