Guarneri Violin Plate graduation plan....
...These are the graduation layout patterns I used for many of my violins. It is a good overall design, (if slightly conservative) and violins with good tone and power have been made using these.
...It comes from rough measurements recorded in Mr. Vigdorchik's book on violin making, as measured in Russia about 100 years ago.
... {I have also had good results using this top plate pattern and the Strad back graduation pattern together.}
Back plate graduation layout for Guarneri (del Jesu) violin. (Meaurements in mm.)
...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 tone is even all over. (see articles describing this in index).
...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.