(Modified 8/2014)
Page AA_38
Guarnarie Violin Top Plate Graduation Plan...
GTX082719
...Next I set my drill press to leave 2.6mm wood thickness (see violin making book coverage for details) and drill many holes and paint the bottoms of those holes with black acrylic geso paint (from an artist supply store). These painted holes will guide us as we remove waste wood from the inside of the plate.
..I mount the plate in a fixture that holds it down at the edges firmly but has clearance space under the plate and begin to remove wood with curved gouge chisels. Watch wood grain orientation so that you cut down-grain at all times. The paint spots narrow as you get closer to final 2.6mm thickness. Try to keep all paint spots about same size as you work.
...Sharp tools are important here. You can lubricate the cutting edge of by rubbing it on a bar of parafine wax to make it cut more freely.
..As you get near to finished thickness, switch to violin making curved planes and scrapers. When all the painted spots just disappear, you are done. ...Once an area is free of paint marks, remove no more wood in that area! Plate thickness uniformity is the goal here.
..The initial graduating of the top plate interior is now finished. The wood at the outside of the dished area, where it transists to the flat section needs to be a smooth curve, rather than a sharp edge, to prevent stress and future cracking.
..When the plate is graduated, determine the tap tones at both the upper and lower bout and record this information. The special tap points are found by watching this instructional youtube video I have produced for you:
..Try for a final tap tone adjustment of 176 HZ for the top plate. For instructions on how to move the tap tone up or down see:
...Now to make the tap tone even all over the vibrating surfaces of each plate (the graduated wood areas), I suggest you use my modified Vigdorchik method of tuning each individual tone strip until the entire plate is even. See separate articles and videos on this method.
(2017) Please use wood of Wood Tone 198 HZ and Rub Tone of # 22 for best results. Please see other areas for more details on these two subjects.
