bigfish -- The spans are measured "cut to cut", or from the leading edge of the thumbhole to the nearest edge of each finger hole. The driller will mark the location of the front and one side of the thumbhole with a grease pencil or scribe, then set the drill bit so that the edge of the bit matches up with these two lines. The location of the front of the hole is set by the two finger spans, and the side is set by the desired center line. The correct pitches will be set into the ball holding jig. -- JohnP