Stradivari violin plate graduation plans...
Strad top plate graduation layout. Measurements notes in mm. Notice that the top is uniformly 2.4mm thick except around the "ff" holes (2.7mm); the sound post spot (about 3mm) and the ends and edges (about 5 mm, perhaps 5.5mm on sides near the "ff" holes).
Strad graudation plan for Maple back plate. Measurements in mm. (again, the edges and ends of plates are left about 5mm)
...The key factor to remember in plate graduating is to end up with a violin plate that has an even tone all over. This is done by making small changes to the above graduation plan so that the tap tone is even all over.
...In addition to this, the back plate must be 1 1/2 semi-tones higher than the top plate. Some makers make the back plate two semi-tones higher than the top plate (on new work) knowing that the top plate's frequency will increase more with the absorption of Ultra Violet light over time (and the varnish curing) so that it will end up 1 1/2 semi-tones apart when the plates are mature.
...This is an important design goal and should not be over looked.
... In addition to this I would suggest that the frequencies you would like to end up with, when the plates are fully mature and stop increasing in frequency, it 322 HZ for the top plate, and 353.5 HZ for the back plate (both even all over of course)
... A side note for the bass bar tuning for the top plate:
...Since it will not be exposed to U.V. light, you should craft the bass bar so that its tap tone (down from the top- tap) is even all along (from one end to the other) and is the same as the goal top plate frequency (that is, the frequency that you want the top plate to end up at when fully mature). This way, when the top plate reached its mature frequency, the bass bar will be the same frequency as the top plate all along its' glue joint.