An Abel hammer (origin from Brooks, don't know beyond that except that it is not a "natural"). First a kerf is sawed down the middle of the molding to the tip. The hammer opens itself up and is measured. The hammer is placed in a vise to hold the molding back together, and the shoulders are each deep needled, 6 - 7 deep insertions per shoulder (3 needle tool, #6 needles, 10 - 11 mm long). Then the opening is measured again. It has increased from 7 mm to 12 mm.