Violin Forum/Message Board

Michael Darnton · Posted: Fri Aug 20, 2021 8:48 pm Post subject:

Recurve is the concave around the edge. Not there on German violins, always there on Italian. It is as wide as it is. Thicker than center on top, thinner than center on back.
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Michael Darnton · Posted: Fri Aug 20, 2021 10:38 pm Post subject: Re: curtate cycloids

Unfortunately, you have just asked for an entire book!

John Cadd · Posted: Sat Aug 21, 2021 1:48 am Post subject: curtate cycloids

John Cadd · Posted: Tue Aug 24, 2021 6:10 am Post subject: curtate cycloids

Michael Darnton · Posted: Tue Aug 24, 2021 8:59 am Post subject:

As I said it is a complex subject. Especially when you don't understand the concept in the first place.
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John Cadd · Posted: Thu Aug 26, 2021 2:26 am Post subject: curtate cycloids

Michael Darnton · Posted: Thu Aug 26, 2021 10:09 am Post subject:

These "complex mathematical" lines are now drawn with computers, but the original method was to roll a disk with a hole in it along a ruler. Many violin makers would probably would be able to manage such a difficult and complex task. I think. Not all, probably, from what I have seen, based on having worked in the business for a while.

My experience has been that it's nearly impossible to convert someone who has not had extensive exposure to fine old instruments AND an open mind to the idea of cycloids, so I have stopped trying. People who have never even held a Strad "know" Strad couldn't have done it, in spite of evidence. . . how can one counter that?
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John Cadd · Posted: Fri Sep 03, 2021 9:13 am Post subject: curtate cycloids

After eliminating all my questions and comments about cycloids I am still not sure why I did that . Maybe the heavy reliance on computers and the way Microsoft suddenly disappeared one of my bookmark pages tipped the balance . Partly it`s my embarrassment to be so far behind the game I just gave up . That`s all I can say about it .

John Cadd · Posted: Fri Sep 10, 2021 8:36 am Post subject: curtate cycloids

Can I clarify the description of the recurve shapes in violin plates .The description included the words Thinner and Thicker . Should that be Narrower and Wider ? Or is this also about plate thicknessing ?

John Cadd · Posted: Fri Sep 10, 2021 8:42 am Post subject: curtate cycloids

Just to keep a connection with the way Strad was thinking ( That is the topic question ) can we guess at the sort of ideas he was playing with ? Because there were no computers in Cremona we have to break the mental stranglehold they have on us today and try to imagine what sort of mental images Strad was working with . Immediate reaction will be "He was a great maker so therefore we can never know ".That sort of defensive attitude .Angels fear to tread etc .

Michael Darnton · Posted: Fri Sep 10, 2021 9:30 am Post subject:

Forget computers completely. This is about a disc with a hole. It is very simple.

The easy way is to choose a disc with a circumference equal to the span between the low spots on the scoop, one disc for each cross template. Place the hole half the height of the arch above the scoop at that template position and draw the template (for purfling to purfling in the c-bout, a 32mm disc with the hole 6.3mm from the center). Do that as many times as you want to make as many templates as you want. You only need to do it once in your life, so it's not that hard--much easier than designing a form.

The result is lines that replicate the situation in real violins---a more serpentine line with a wide scoop when the arch is wide and low, becoming puffier towards the edges with a narrow scoop when the arch is high and narrow. It is this changing character of the arch that is exactly the same in cycloids as violin arches that is impossible to replicate any other natural way that is so convincing for this method because it naturally matches what exists in the best old Cremonese violins. This situation is not matched--and is often very different--for violin of other schools and times, including the instruments of modern makers who try to replicate old ones by eye alone.

Placement of the scoop? So that the rise past the bottom of the scoop towards the edge is precisely the height of the crest of the edge at the crest of the edge. Thus, farther in when low and wide, farther out when narrow and high.

This is very simple and really requires no thought at all. It also does something that is impossible for EVERY other method: it makes the all of the cross archings exactly the same, mathematically, even though the look different. I believe that mathematic match through the whole violin makes the arch move as a unit, rather than randomly as would happen with a guessed arch.

Notice that all heights are from the bottom of the scoop to the top of the arch at that position---they are not measured from the bottom of the plate.

If you had access to a lot of old Cremonese violins of different periods you could watch how this method changed in details over time--from a purfling-to-purfling scoop to the scoop moving inwards and becoming deeper, then whole templates being discarded for half ones, which offer more flexibility, sometime around 1650 (very early). Some people have made the argument that this couldn't be the method because whole templates don't fit Strads, and that's true, because by that time whole templates weren't being used. This does not disprove cycloids, obviously.
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John Cadd · Posted: Sat Sep 11, 2021 4:23 am Post subject: curtate cycloids

Thankyou for an excellent explanation Mr Darnton . Now I understand. No problem with that at all .
Is there ever a difficulty with wolf notes happening in those recurve areas ? The video with Edgar Russ seems to point to that recurve zone in his explanation .

Michael Darnton · Posted: Sat Sep 11, 2021 8:33 am Post subject:

Can you point me to the specific video where he talks about this?
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John Cadd · Posted: Sat Sep 11, 2021 5:25 pm Post subject: curtate cycloids

The article and video are at ; https://www.violincellomaker.com2021/05/07/wolftones/
I was interested in the areas he indicated in the recurves at the widest areas .
This reference does not work here but it comes up if you just use English words. Edgar Russ Wolf Tones . The written section is a faithful copy of the video dialogue .