My "Plowden" project

[HoGo]

Here are some basic drawings of Plowden del Gesu of 1735 I cobbled together. No scroll, yet. I will work on more as time permits.

They are pdfs A3 format thay should print in full size if printed to 100% (and if you can trust your printer).

Enjoy!

PlowdenBack.pdf PlowdenRibs.pdf PlowdenTop.pdf

[Renegade Violin]

Wow, how will you cut the purfling with such irregular contours?

[HoGo]

You should ask how ole Bartolomeo did it .

Just make the outline irregular and use slightly blunt tool at a bit faster pace and you'll get there eventually .

[Michael Szyper]

nice drawing, really cool! If you conclude that irregularities are due to edge wear, tracing the mold after the purpling might be an option. After the purpling job is done, you can add the edge wear (if you want do to an exact copy) 

[Renegade Violin]

15 minutes ago, Michael Szyper said:

nice drawing, really cool! If you conclude that irregularities are due to edge wear, tracing the mold after the purpling might be an option. After the purpling job is done, you can add the edge wear (if you want do to an exact copy) 

As you say. Maybe two contours should be made, the one that is already there and the 'primary' one. Cut the contour after the 'original' line, then do the 'material wear'. 

[HoGo]

I didn't follow all the worn out "steps" at the hard summer grains on the top edge in the drawing. The back outline is more reasonable for making mould and in this case also much more symmetric.

[Michael Szyper]

5 hours ago, HoGo said:

I didn't follow all the worn out "steps" at the hard summer grains on the top edge in the drawing. The back outline is more reasonable for making mould and in this case also much more symmetric.

the back outline is worn heavily, too. In making copies people should keep in mind that the top is the "face" of a violin with all its asymmetries and idiosyncrasies. Therefore I would step away from giving a general recommendation how to derive a template from, since it really depends on where you want to go. 

[HoGo]

Here is comparison of four other +-1730's del Gesu backs against purfling line of Plowden. You can interpret it how you want but I see they are shockingly similar, pretty much exchangeable.

I just took snapshots in Photoshop so upper halves are cropped (the upper halves tell the same story), they are all remarkably similar and deviate mostly in corners and if one corner on a side is shifted then the other one is typically shifted to the same direction which agrees with the Hargrave articles on Cremona method and Guarneri's use of possibly one mould. If I were to reconstruct the mould I'd take the backs a guide. The tops of these violins show varying random deviations from the shape or symmetry visible on back and also very worn edges. which suggests he wasn't all that precise when he was closing box or tracing tops from ribs.

If you want to do a copy you'll need to have the original at hand and replicate each and every error that del Gesu did.

[JacksonMaberry]

On 5/23/2023 at 7:28 AM, HoGo said:

If you want to do a copy you'll need to have the original at hand and replicate each and every error that del Gesu did.

Right. But I think it's more fun to make all kinds of my own errors! 

[HoGo]

One more thought for me (and anyone other interested)...

I tried various of the methods for drawing cremonese violin mould and couldn't get satisfactory result for the C bouts of a generic Guarneri model...

I re-read Hargrave and checked many older resources about dG and here is something that is in my mind:

1. Hargrave mentions del Gesu used smaller overhangs inthis period, well below 2mm, down to 1 mm and later went to more "normal" 2+mm.
2. I overlaid ten or so different dG violins and found that unless the model is much larger (like Kreisler), the ribs are very similar to identical. On the larger models it's mostly the overhangs and upper bouts that makes the violin larger (starting with outside curves of the upper corners), the bouts ribs are basicly identical to smaller ones.

Looking at the Plowden, the C-bout curve IS ALMOST PERFECT ELLIPSE. Most of the circular constructions of the Strad forms use one large circle for the main part of the bout and two smaller to finish the corners, buthere this approach leads to discrepancies from real outline that I don't like at all. These circles don't approximate the shape of ribs or purfling well enough and they also create unsightly kink in curvature. I can get better result if U use sevral circles of diminishing radii, but just to get to the block cutout two are barely acceptabe to copy the curvature and at least one or two more would be necessary to approximate the very corner shape.

I mostly was looking at the curve of purfling and outline of several examples that match so well that it cannot be just lucky accident. The ribs generally follow the curvature except for very corners which deviate in shape even between opposite corners of the csame violin , so I didn't follow those too close.

I'm thinking how could dG get so nice smoth and symmetric (upper to lower point) elliptical outside curves if he followed his crooked ribs, especially at corners. My first ide was that he started with nice outline on his form (OK corner blocks were not as precisely carved as Strads), transfered it to the back plate and cut it out close to the line (depending on the period he might have used different distances) and finished the c-bouts and corners to template, thus the nice outline, but after he removed ribs from mould and nailed the neck and needed to adjust the alignment of neck when gluing back to ribs he wasn't all that careful to get the overhang same as before marking or even nudged the corner blocks wherever they would fit inside the plate outline, ending with quite wild ribs. If his rib bending was uneven or they sprung back too much that would increase chances of some deviations as well after removal from mould.

Now that I'm drawing the form I'm tempted not to follow the outside of purfling line as is standard which would require larger overhangs than original model to get the same plate outline but rather make slightly larger mould (trace ~1 mm outside the purfling) and count with smaller overhangs to start with so I will get the same outline AND body volume and actual "active" plate surface as on model. I could then use the same mould for making the larger dG by simply marking larger overhangs or "packing" the mould in the upper bouts like Hargrave suggests.

What would be your take on constructing dG mould? Geometric or free tracing? Larger or smaller outline?

I attached snippet of the perfect ellipse vs. bass side of Plowden (which matches quite a few others) and standard "four-circle" ellipse approximation (notice the deviation from the real ellipse).

 

[Don Noon]

1 hour ago, HoGo said:

Looking at the Plowden, the C-bout curve IS ALMOST PERFECT ELLIPSE.

What would be your take on constructing dG mould? Geometric or free tracing? Larger or smaller outline?

I don't recall my exact development, but I ended up with two ellipse segments.  The lower segment gets almost completely out to the corner, while the upper segment is somewhat tighter curved, with a circular segment spliced on to get more "hook" to the upper corner.  Nowhere near as hooky as Strad, though.

Since I'm using CNC and designing on Fusion360, it only makes sense to design geometrically, trying to match the appearance of dG fairly closely.  I have 4 dG-based molds, for LOB's of 352, 355, 358, and 400 mm.  That last one is the viola, with lots of liberties taken, but trying to keep the general look.  For all of the violins (and moreso the viola), the C-bout width is slightly wider, proportinally, than dG fiddles.... just because I think it might sound more like what I want, but without any convincing evidence.

[Arsalan]

On 5/22/2023 at 2:02 PM, HoGo said:

Here are some basic drawings of Plowden del Gesu of 1735 I cobbled together. No scroll, yet. I will work on more as time permits.

They are pdfs A3 format thay should print in full size if printed to 100% (and if you can trust your printer).

Enjoy!

PlowdenBack.pdf 90.39 kB · 71 downloads PlowdenRibs.pdf 89.66 kB · 44 downloads PlowdenTop.pdf 92.97 kB · 62 downloads

Thank you very very much HoGo 

I was looking for them … do you have any more Guarneri 

And may I know how did you make those drawing ? Based on any poster or actual picture of the instrument? 
im looking for sainton , and common too 

I really appreciate if you know how I can find those 

[HoGo]

I started with good photographs and verified dimensions and CT scans of the violin. I put those resources together in Photoshop and resized all to full size and then traced outlines to my best ability and then exported to Illustrator to create the pdf's. There are many nice looking pictures on web that have actually quite large distortion in them (probably taken with phone or at small distance), I had to select the few that showed the least distortion for the core of my work.

I posted similar tracings of Kreisler year or so ago. I also have CT scans of some other violins and resized some other dG to full size for comparison though I didn't do all the research and verification of their dimensions like I did for Plowden, and just did a quick check.

BTW, the comparison pics above are of Du Diable, Haddock, Kreisler and CT of unknown (to me) Guarneri of 1730.

[Don Noon]

6 hours ago, HoGo said:

I started with good photographs and verified dimensions and CT scans of the violin. I put those resources together in Photoshop and resized all to full size...

That's how I made my first Plowden-ish model, except I used a copy machine to upsize a poster, and worked directly with that.  For the CNC model, I took a survey of several dG dimensions, and synthesized my own models from that.

[Michael Darnton]

1731 Strad. I did this a couple of years ago. A Bros Amati maps to a slightly better ellipse. The problem is in the armpits, as you can see.

[HoGo]

Strad models are actually quite conforming with three circle bout geometry. One large circle and two smaller ones that fit the curvatures right into the corners.  I see that you (Michael Darnton in previous post) put the upperpoint to lower point by rotating the body instead of mirroring that I think of in this context. The rotation tends to blend or "average" the upper and lower circles into similar radii producing more elliptical or oval shape. Most Strads have more of an four circle "egg" geometry when mirrored, the upper circle with slightly smaller diameter than the lower circles while typical del Gesu produces very precise smooth ellipse with no detectable trace of circular geometry behind.

Amati's look quite elliptical as well, though a bit "thicker" ellipse but I haven't checked that yet. Perhaps that's part of the Amati grand pattern geometry that Strad had thrown away and created his own models but Guarneris stayed closer to the original design...