Violin Forum/Message Board

[Michael Darnton]

Ya gotta drill a pilot hole first, then press the nail in. Hammers just give grief. But there's a good reason they stopped doing it: wood shrinks, nails don't. Screws are a little better--you can tighten them up when the wood shrinks--but be sure to use stainless steel.

[John Cadd]

About curtate cycloids --Assuming makers in that era had no Spirograph available can you picture makers using thin strips of wood and bending them by hand ,thumbs inside , fingers out.Or as I did once when making a headboard for a double bed ;Bend a half curve ,then repeat the mirror image for a whole curve.
What started off as a tryout shape could have been tidied up with compasses to make it more formal. From the perspective of the wood itself ,maybe the wood was happier to have that type of curve imposed upon it.
Using nature as an inspiration was not foreign to makers with an artistic sense.If you glance at a scroll you can see a connection with a wood shaving from a plane.
The Sacconi book does have at least one reference to the word Catena(think that`s how it`s spelt.)
I have wondered if the curtate cycloid is close to a parabola with a separation in the middle to allow for the bridge feet.
The aim must have been enough stability and yet allow for a bit of wobble as well.Comparisons with bridges can be misleading as a bridge is a narrow isolated shape in comparison with a violin plate
The bridge centre is on it`s own ,so to speak.
These are perhaps half formed ideas but these sites are best if a brainstorming method is accepted.The rule is to let the ideas in and not put the brakes on too soon.
The whole parabola across would be similar to cutting the back with centre of thickness right where the post touches,Like standing at the centre of a seesaw and ending up with no movement.

[Michael Darnton]

Cycloids automatically define EVERY aspect of a good arch--you don't have to bend and twist things to get the little details you want as you do with other methods. Your suggestion of using a bent stick is similar to suggesting drawing a circle by hand when there's a compass sitting there on your desk.

[M.Lange]

I read somewhere, that the lowest point of the cycloid generally is
- inside the violin outline on Amati's,
- on the outline on Strads and
- outside the outline on del Gesù violins.

What do you think is that correct?

Matthias

[Michael Darnton]

I think that general rules like that are very dangerous. Del Gesus from the mid-1730s have the scoop farther in than most Amatis, as do a lot of Strads from the beginning of the 1700s. Putting the low point outside (or on, for that matter) the outline would make closing clamps slide off, and the only makers I'm aware of who did that are da Salo and certain late Guadagninis.

[M.Lange]

Thank you, Michael. I understand that general rules are dangerous. It just would have been nice to have a easy way to characterize the different archings.

I found out were I read that statement. It was on the Schleske site.
I think I did not explain it well enough.
For example on the Brothers Amati on your website, the lowest point of the cycloid (where the horizontal black line is) is inside the edge.

I think Schleske does not consider the edgework.
If you would cut the scoop with the same gouge on a Amati, a Guarneri and a Strad arch, then
- the Amati arch would rise towards the scoop
- the Strad arch would descend towards the scoop
- the Guarneri arch would descend steeper towards the scoop

In either case the closing clamps would rest on the edge.

I hope this is a better explanation. I couldn't find a picture that illustrates it.

Matthias

[Michael Darnton]

The problem with violin people, and I suppose it's true for everyone, is that far too often they get an idea, develop a statement of it, then look for data to confirm it, ignoring everything that contradicts the developed concept. I think this is another example of that.

[violinarius]

[violinarius]

[violinarius]

[violinarius]

amezcua - If you like to read on tuning plates, then perhaps you will enjoy these two web-sites.

http://www.platetuning.org/html/arching_and_thicknesses.html

http://www.dalemfg.com/violin_001.htm

I hope you find these helpful in your quest.

[John Cadd]

Well gentlemen, a small pat on the back for you all as we seem to be top of the pops with most replies today.Any new maker short of a tutor has an Alladin`s cave of advice to absorb.
At this rate Mr Darnton will be easing ahead of Herron -Allen in the History of Violin-making Stakes. (6/4on)
Would it be a good idea to include the word ARCHING in the title as a separation of topics would not make much sense at this stage?
Why I was asking about "twisting " wood was a query about the knowledge of this type of mathematics in those days.Pockets of knowledge must have been available for the priveliged few.The Church across the road may have been a contact through the priests who must have taken more than a passing interest in Stradivari`s work. There is (to me ) nothing obvious in the shape of a curtate cycloid that shouts "Yes , this is the one to use".I am still probing to get an understanding of it`s properties,generally
The list of books given earlier included one of my favourites;The Book of Curves,which has many elegant mathematical revelations.
The open window allowing a soft breeze to shift the curtain reveals a curve to describe the way the edge of the curtain moves.
I must look to see if thin bits of wood have a formula of some kind.
So , looking at one of the finest violins ever made--the Oistrakh with the one piece belly,how much has that been researched?
If I was going to make just one instrument in my life I would pick this model .No idea where a piece of wood that wide would be found though.Were there any unusual features in arching or thicknessing? As a "listener" I have never heard the particular sound quality of that violin before or since and it must have been played since Oistrakh died ,surely.

[Chet Bishop]

Regarding the math level of folks in Amati's day, say, or certainly Stradivari:

Leonardo da Vinci died in 1519, and certainly had all the math they could have needed, nor was any of it secret. Geometry and Trigonometery had been around for centuries, Algebra for over two millennia, and Calculus had been worked on for years but was first published by Leibniz, as a finished concept, about 1684, with Newton right behind him.

I really doubt the concept of Hypocycloids (curtate cycloids) was too advanced for that time.
_________________
Chet Bishop
https://bluefiddles.com
https://fivestringfiddles.com

[Andres Sender]

You didn’t even need to have the concept to understand the concrete effect of playing with discs with holes in them. They may simply have called them “button curves” or something like that.

[Chet Bishop]

What?!? They had buttons? They didn't just bind on their rawhide tunics, with thongs of the same material??
_________________
Chet Bishop
https://bluefiddles.com
https://fivestringfiddles.com