In order to extrude curb over pins a special curbform is required. It requires the curb height to be at least 5″ greater than the pin height. For example, if the pin height is 2″, the curb needs to be at least 7″ high. The additional height allows for the centerline of the auger to be raised to clear the pins while extruding and allow for sufficient free flow of material through the form. The front of the form has an opening to allow the operator to steer the form directly over the pin. The opening has rubber flaps to allow the pin to enter the form but restrict material from exiting the form.