I recently (3 July) purchased a Rigid Oscillating Spindle/Belt Sander. When I have the unit set up as a spindle sander, the spindle travel up and down is smooth and continuous. However, when I install the belt sander assembly, the up and down motion of the sander is no longer continuous, rather the belt assembly does not appear to make the full downward stroke. When it gets to the lowest point of travel, it pauses (the equivalent time as if it made the full cycle) and then goes up. Is this normal or do I have something not assembled properly?