Here is the Huon Pine soundboard. I will glue the two lengths edge to edge, cut the resulting board more or less to size – and then plane it down to about 1.6 mm.
Thereafter, a cabinet scraper comes into play: centuries of experience has established a formula for the thickness, which changes from edge to centre. The area reserved for the George Gerle rose will be about 1.2 mm thick.
You can see from the photo why my home-made gauge is made the way it is: I can use it to check and double-check each and every point on the soundboard. The various thicknesses are meant to enhance the quality of sound, or – we could say- the resonance.
Another finicky task – but worth doing properly….