Abstract: A woodworking machinery jig and fixture system includes a track which is or may be attached to a fence, a convex-concave curved flip stop and a base which mounts the stop to the track. The stop has a projecting portion which penetrates the plane of the fence so the stop isn't lifted by the point of a mitered board. The stop also has a lower convex surface which faces the work support surface and curves up at both ends. The top leg of the stop is concave toward the fence to allow clearance for a zero-clearance board and make the stop adaptable to different track and fence configurations. The base has opposite sides of different widths bordered by steps on one side and a ramp on the other side so the base can be used in a large range of T-track slot widths. The arm mounting hole of the base is offset from the base mounting so as to provide an offset to accommodate a ¾? zero clearance board by turning the base a half turn relative to the slot.