Minimum top thickness at sound post

[baroquecello]

Dear maestronetters, I recently had a very unpleasant experience with a relatively newly made violin by a relatively well known maker from a germany, which got a Sound post crack. It was discovered by another maker when he inspected the violin before starting a Sound optimisation. (which he didn't do then, ofcourse). The violin received a new top for half the usual Price, but now the new Sound post scares me, as it is clearly visible through the top, and, seen from outside, seems not to fit very well. 

After the inspecting lutier found the SP-crack, he checked the top thickness using one of those digital devices. It seemed the top in the SP-area had a thickness of about 2.7MM. I don't know what the thickness of the new top is, but I suspect it is similar, as the maker of the violin seems to have his theories about how to make a good sounding violin. (and he is not unsuccessful, many professionals Play his Instruments).

Now to my question: for your own making or generally speaking, would you consider 2.7MM acceptable or too thin in the SP-area? What would your minimum and your maximum be and what is what you usually do?

[David Burgess]

2.7 is in the ballpark of what one often sees, but I go more like 3.3.

If the soundpost is "printing through" early on, that does suggest a poorly fitting post.

[uncle duke]

48 minutes ago, baroquecello said:

Now to my question: for your own making or generally speaking, would you consider 2.7MM acceptable or too thin in the SP-area? What would your minimum and your maximum be and what is what you usually do?

Sorry to hear that and my opinion just based on what I've learned in the last few years is yes, 2.7mm sp area is or more than likely is, not thick enough.  I'm not a professional maker, just a hobbiest - I can't see a pro here giving away what they'd do so you can have my opinion.

  I checked my plans for a Strad of some sorts and a D.G/ Maggini  and their soundpost thickness areas are considerably thicker on paper.  4.41 or .174 for D.G. and the Strad just slightly thinner.  That's not really thick when you see the belly rise relatively easy when it's soundpost setting time.   I feel safe staying with those specs.

 Now if I could convince myself that I don't need 1.6mm thick outer bout areas all of the time I may just be able to get to the next level of making assuming there is a next level.

good luck baroquecello 

edit-  on a whim I went out and found a micrometer that was open already.  Using intuition only I turned the adjustment to close the gap and stopped turning where I thought the best thickness for a soundpost thickness for a belly would be best.  I stopped at .181 which equates to 4.59 mm.

[kyproset]

The thickness of my 1857 Vuillaumes's SP area at the top is 2.4, 2-5mm  and I was told it's way too thin, so I'd better be careful.    

[Torbjörn Zethelius]

A badly fit soundpost will crack any top.

[duane88]

1 hour ago, Torbjörn Zethelius said:

A badly fit soundpost will crack any top.

exactly! 

I hate to go under 3.0 on a new instrument, but have seen plenty, old and new, that are thinner and are just fine.

 

 

[christian bayon]

I go around 3.2. Many  contemporary  instruments are way too thin (blame the Strad posters) and even not able to avoid the neck projection going down.

[chungviolins]

This is my measurement: 3.5 mm

KYC

[David Burgess]

1 hour ago, christian bayon said:

I go around 3.2. Many  contemporary  instruments are way too thin (blame the Strad posters) and even not able to avoid the neck projection going down.

Genuine Strads too. On a multi-million dollar instrument, most owners won't protest too much about putting out a few thousand dollars occasionally.  The expectation goes much differently with contemporary instruments.

[Alex l. Reza]

I build pretty "stout" instruments and usually stay around 3.3-3.75 at sound post.  I have seen many newer contemporary instruments with 1.9!!!  and the edges down to nothing also.  Makes me wonder how they would stand up over time.  

[JohnCockburn]

Is this turning into an organ swinging contest about who makes the thickest soundpost region? 

[arglebargle]

I don't graduate the soundpost area at all.

[Melvin Goldsmith]

I put across grain laminate patch  in there and keep it around 3.5mm.....kinda like what I know works

[Guest]

3 minutes ago, Melvin Goldsmith said:

I put across grain laminate patch  in there and keep it around 3.5mm.....kinda like what I know works

Do you use Maple or Spruce?

[Melvin Goldsmith]

spruce

 

All the top concert fiddles have a spruce laminate  in the S P area... fact

[Conor Russell]

I just make the whole thing out of plywood. And I can buy it at my local hardware. It's fab.

[Stavanger]

Carved bassbar is so 1900. The new thing is carved soundpost.

[Brad H]

9 minutes ago, Stavanger said:

Carved bassbar is so 1900. The new thing is carved soundpost.

Ha ha!  At least you know the top of the sound post would fit!  

[kyproset]

So gents, what is the thinnest acceptable measurement for the SP area?

[baroquecello]

8 hours ago, Melvin Goldsmith said:

I put across grain laminate patch  in there and keep it around 3.5mm.....kinda like what I know works

is that 3.5 including the Laminate patch or dos that come on top of it?

[uncle duke]

2 hours ago, kyproset said:

So gents, what is the thinnest acceptable measurement for the SP area?

Having a violin like yours first makes me think did Vuilluame make a Strad copy or a Del Gesu copy.  Next would be did he copy another first class maker other than those two or did he make a violin following his own scheme.

As for present day making maybe make an average of all the answers you have here above so far for an answer but not necessarily the answer.  Grain line spacing, following a specific plan and the nature of the wood are probably why there's not just one answer for a soundpost area thickness. 

  Maybe treat yours as a 450 year old instrument rather the a 200 year old instrument - be careful.

[nathan slobodkin]

4 hours ago, kyproset said:

So gents, what is the thinnest acceptable measurement for the SP area?

The one that doesn't collapse or deform during the original owners lifetime, Sounds OK and doesn't crack unless it's in an accident or falls into the hands of some self invented set up scammer.

Looking back through my records I have used anywhere from 2.7 to 3.3 for violins over the years with various archings, sizings and models. Feedback has been that my instruments are pretty low maintenance.

[nathan slobodkin]

12 hours ago, Melvin Goldsmith said:

I put across grain laminate patch  in there and keep it around 3.5mm.....kinda like what I know works

Melvin,

I am assuming you are talking SP patch size. Does this allow you to make a thinner chest area than if you were blending away from a carved in thick area at the post? Is that why you do it?

[Don Noon]

6 hours ago, kyproset said:

So gents, what is the thinnest acceptable measurement for the SP area?

Depends on who's doing the accepting.  There is no set standard or stress calculation that will give "the" answer.

It "should" also depend on the properties of the wood; high density with good crossgrain strength could be much thinner and give the same durability as much thicker, low-density splitty wood.

I use a small maple patch to prevent denting, in addition to leaving the general area thicker.  Normally ~3.2 plus the 0.5mm patch.

[Michael_Molnar]

I feel that the SP patch ensures a better transfer of SP vibrations into the spruce plate fibers. Some makers complain that the maple patch can be slippery which lets the SP slide with time. So, I scuff mine up just a bit.