violin/component weight

...A good violin maker I met at the North West Handmade Instrument Show in 2006 said that a completed (full sized) violin ready to play (but not counting the chin rest) should weigh no more than 400 grams. -Get as close to this as possible without sacrificing frequency goals of plates.
...I got to thinking about his advice and decided to put some of my violins on a strict weight diet. By adjusting my plate graduation plan I was able to approach this standard and I am here to tell you that it does make a significant difference. Most of the over-weight was in the back plate being too thick so as the weight is reduced the tone really picks up. (do not go too thin however!)
...It is good to remember that we still want the violin plates to be of a certain frequency;
I would strongly suggest 213 HZ for top plate all over evenly (begin with the top plate graduated to 2.6mm even all over (except edges and ends of course) and then adjusted to an accurate 213 HZ all over. (see new tap tone technology section on adjustments.)
...The top plate should weigh about 60 grams, 64 grams with bass bar; and back plate about 97 grams. This is based on a relative densities of: 0.424 for top plate spruce wood and 0.645 for maple back plate wood (compared to water); {a 2 to 3 ratio}.
...We want back plate to have a tap tone of 242 HZ all over. (see new section as above).
called : Tap Tone Project and Tap Tone Technology...study all articles for full details)

. Here is a estimated weight schedule for the parts of a full sized violin (14" body length); remember that 400 grams is our target weight.

Completed instrument; ready to play (but with out chin rest) {chin rest with steel clamps adds about 50 grams}:

Top Plate; unvarnished with bass bar............57 grams

( Bass bar weight................................................4 grams)
Top Plate, unvarnished with out bass bar........53 grams
Top Plate varnished, with bass bar..................64 grams

Back Plate by itself, unvarnished....................90 grams

Back Plate varnished..........................................96.7 grams

Rib structure with 6 wood blocks.....................55 grams

and liner strips, finished and unvarnished.
Rib Structure varnished...................................... 59 grams
*Neck, finished to final size................................70 grams
Neck, finished and varnished.............................72 grams

Fingerboard.....................................................64 grams

Tailpiece, strings, fine tuner with tailgut.........26 grams

Tuning pegs; fitted (set of four).....................16 grams
End pin...............................................................2 grams

Bridge.................................................................2 grams
Sound Post........................................................1 gram

Oil varnish; 7 coats............................................19 grams

-------------------------------------------------- ------------------
Total weight................................................... 402 grams

...Please believe me that the above weight guides are possible and necessary for a truly successful violin. I hope they will be a useful guide to you can prevent an overweight problem before it is built into your instrument. I would suggest that 400 grams should be the goal instrument weight, ready to play but without chin rest. (Typically, the chin rest might add 50 grams weight, so 450 grams with chin rest attached).
{..Allow minus 2% weight for 13 7/8" instrument, and plus 2% weight for 14 1/8" instrument.}

...Here I would like to say a word about the relationship of the weight of the
top and back plates of the violin. I suspect that there is an ideal relationship
between these two but I can not say now, what it should be for certain.
... However, I do suggest the following saying is a possible workable guide:
"Let the plates weights be in ratio to their relative density."
...This proposed guideline will then allow you to adjust for differing woods.
...Based on careful measurements of well seasoned instrument making wood I
have on hand, I discovered that:
*** Engleman Spruce top plate wood has a density of 6.88 grams per cubic inch.
*** Flamed Maple back plate wood has a density of 10.645 grams per cubic inch.

<>Thus the ratio of these two is (spruce/maple)= 0.646
<> the ratio of (maple/spruce) = 1.547

...You can measure and weigh a test sample of your material or use the above as a
guideline for matching plate wood for your instrument.

...As an example; if your top plate (unvarnished) and ready to glue into the completed violin body), complete with bass bar and cut out "ff" holes weights 57 grams then the back plate should weight (57 * 1.547) = 88.2 grams.
.. Conversely, if your back plate was finished first and weighs 90 grams, you might consider a top plate weight goal of: (90 * 0.646) =58 grams. (with bass bar/ 54 grams with out bass bar),
...Remember that along with the proper weight, we also want the plates to have certain even-all-over tap tones: for the back plate 198 HZ; and 176 HZ for the top plate.
...See 'Useful tools' in tap tone technology section and make the wood sound reference tool ... you really will need this new tool (calibration sound file is included to set up.)
...The overall weight of the compelted instrument to be 400 grams (with out chin rest) fitted up and ready to play. If a choice must be made, I would make the instrument plates as light as possible while still maintaining theplate tap tone frequency goals.

...In conclusion, it is a lot easier to build with component weight in mind, so that the sum of the parts does not turn out to be so heavy that it can not vibrate freely.

(c) 2020 David Langsather Salem, Oregon, USA

..Here is some data from OberlinAcoustics site:
Violin:............Viola:.................Cello:...........

Top Plate:
65grams.........97grams..............434grams
(59-71)............(88-106)................(412-516)range

Back Plate:
109grams..........148grams..........673grams
(101-117)............(135-164)...........(630-716)range

...Top plate weights of nine famous Old Italian instruments (from VSA papers summer 2006):
60 grams average and 64 grams with bass bar.
..Remember that these are with varnish. If 70% of varnish weight are on the two plates, then each plate would have: {0.70 * 19grams/2=6.67 grams varnish leaving:
57.33 grams for top plate without varnish and with bass bar and a suggested back plate weight of 90.33 grams without varnish.
..thus the varnish is (6.67/57.33)=11.6% of top plate total weight and (6.67/90.33)=7.4% of back plate. It is easy to understand why varnish has an effect on violin tone qualities.

...Simon Chambers (www.simonchamberstonewood.com) has posted a survey
of 'ideal' tone wood relative densities (specific gravity)(compared to water), which seems a good guide for instrument makers intent on making an excellent instrument.
  He suggests a range of 0.32 to 0.36 densities (as compared to water) for spruce top plates. Other information he has, gives an acceptable ideal range of 0.34 to 0.40.
  For maple wood for back and neck, he suggests a range of 0.53 to 0.60.
  These average out to 0.37 for spruce wood and 0.565 for maple wood.[2 to 3]
  These are compared to water, which weights 62.4 pounds per cubic foot; or 16.394 grams per cubic inch.
  Thus spruce wood we use should be from 5.24 to 6.56 grams per cubic inch.
   and the maple wood we use from between 8.69 to 9.84 grams per cubic inch.

Some conversion units:
454 grams per pound weight
water weights 62.4 pounds per cubic foot
1728 cubic inches / cubic foot
specific gravity is ratio of wood density compared to water density.
less than 1.0 floats and greater than 1.0 sinks in water.

  Now let us say we know out wood is a bit on the dense side; we wonder how much we should reduce the graduation diminsions given for our plans to compensate for the differing wood density and wood stiffness?
  As a rough guide, may I suggest the following method.
{for out rough calculation, I will assume that the stiffness is directly proportional to density increase and that stiffness increases by the square of the thichness increase.
  So, for example, if our top wood has a specific gravity of 0.42 by measure and weighing and our goal average is 0.37; we know the density is: (0.42/0.37 = 1.135) or 13.5% too dense. Thus we need to make the graduation thickness smaller to compensate. I am assuming that this means the stiffness will also be 13.5 percent too much.
  Since the wood stiffness goes by by the square (twice as thick is 4 times as stiff); what fraction times itself equaly 0.135? 3.68 comes out by experimenting with the calculator. So is I make the graduation depths; (1-{0.0368) times the pattern IE:0.9632 times X.
  So if the pattern says 5mm; I will leave 5 mm X 0.9632 = 4.82 mm instead.
  This should give us close to the correct acoustical properties of our completed violin.
  Of course, check plate weight to above chart and also get the tuned frequencies to 213 HZ for top plate and 242 HZ for back plate as a priority.
  Good building....