Scrapers at the Museo del Violino in Cremona

[Ch. Dequincey]

I’ve been looking at making scrapers based on those in the collection at the Violin Museum in Cremona  (MS 691 up to MS 697). To work out their outlines, I’m using the pictures and measurements provided by  the catalogue of their collection  . (https://museodelviolino.org/en/nuovo-libro-antonio-stradivari-disegni-modelli-forme/). 

During the process a few questions came up and I’m wondering if participants of this forum would have answers? 

1)While resizing the outlines to the measurements provided by the book, most of them worked pretty accurately besides the MS693 which seems slightly narrower when proportionally adjusted to length and most importantly the MS696 which is about 6mm longer when proportionally adjusted to the width measurements.  

As the book gives the exact same measures for the MS696 and the MS697, the latter fitting within the measurements provided.  

I’m wondering if it could be a mistake during the data recording/entry? Or a photo distortion that could have happened during the editing? Something else? 

(please ref to snapshot provided, the frame representing the size provided in the book). 

2) Has anyone had a chance to look at them out of their display box? And if so, have measurements of the MS696? 

3) Is there any record of their thickness available? 

4) Are there bevels on one side only or on both sides for each of them? 

 

Thank you for your insight,  

 

Edited December 1, 2023 by Ch. Dequincey
Posted it before finishing to write the text

[Davide Sora]

At this link you will find the scale drawings of Stradivari's tools made by Addie and hosted on Peter Grankulla's website. If you scroll to the bottom of the page you will find three printable PDFs for scrapers:

https://drive.google.com/drive/folders/1IIrVDvOC3-KS6YjwdrP9jmUvpdURcS08

The narrow and rounded ones seem to be double-beveled, and the others seem to be single-beveled, but I'm not 100% sure because I've never held them in my hand. In any case they have a single cutting edge.

[Nick Allen]

2 hours ago, Davide Sora said:

At this link you will find the scale drawings of Stradivari's tools made by Addie and hosted on Peter Grankulla's website. If you scroll to the bottom of the page you will find three printable PDFs for scrapers:

https://drive.google.com/drive/folders/1IIrVDvOC3-KS6YjwdrP9jmUvpdURcS08

The narrow and rounded ones seem to be double-beveled, and the others seem to be single-beveled, but I'm not 100% sure because I've never held them in my hand. In any case they have a single cutting edge.

I'm pretty sure that they are offcuts from old swords of the time. 

I don't think it's really necessary to copy them to get a desired result in a violin, though. But if you want to make replicas, hunt down some old swords and have at it I guess. 

[Davide Sora]

2 hours ago, Nick Allen said:

I'm pretty sure that they are offcuts from old swords of the time. 

I don't think it's really necessary to copy them to get a desired result in a violin, though. But if you want to make replicas, hunt down some old swords and have at it I guess. 

I think you're right, they look like pieces of sword blades, probably a great source of good steel in those times. I have done some tests with similarly sharpened scrapers, but I have never been happy with them, I remain fond of my good scrapers, sharpened at 90° with double-cutting edge, apart from one.

 

[John Harte]

From photos like the first below, I had assumed that these scrapers were double beveled.

The second photo features some of my scrapers made along similar lines.  These took a while to get used to but I have come to like how they work.

[Davide Sora]

51 minutes ago, John Harte said:

From photos like the first below, I had assumed that these scrapers were double beveled.

The second photo features some of my scrapers made along similar lines.  These took a while to get used to but I have come to like how they work.

As usual you are right, from your photo taken from the old museum, with better lighting and angle I would also say that they are double bevels, my memory is starting to show signs of failing...

I have to ask the conservator to see them outside the box, so maybe I can also measure the thickness.

[John Harte]

1 hour ago, Davide Sora said:

As usual you are right, from your photo taken from the old museum, with better lighting and angle I would also say that they are double bevels, my memory is starting to show signs of failing...

I have to ask the conservator to see them outside the box, so maybe I can also measure the thickness.

I'm not right yet.  I look forward to hearing of what you discover if you do get to see them outside the box! 

Maybe adding weight to my best guess, old sword or knife tips would most likely be double beveled.  However a double bevel might not be so for all the scrapers.

I suspect that the scrapers are much thicker than the 1.6mm that I mostly used.  Stiffness was a consideration but creating an edge on thicker steel would have taken a lot longer...

[Ch. Dequincey]

 

 

Thank you for the pictures and link. What a formidable source of information! 

I printed the three scrapers related pdf at 100% (no shrinking, fitting etc.). The size of scrapers outlines seems to differ from the regular A4 and Letter to the other one 4-A4 at first sight. I will look into it in more detail a bit later.

That said, the 4-A4 one seems closer size wise even though slightly bigger than what I came up with following the measurements from the catalogue. I assume these are to size or? 

If you get a chance to look at them and measure the thicknesses that would be wonderful. I'm wondering as well about the MS 696's length and width as on the prints it looks definitely bigger!

Bevels on both sides seems a bit unusual for scrapers. This said, why not? I use some of my knives as scrapers in some instances.

I'd be curious to know if the type and behavior of the steel, is a factor for the double bevels and their angles, or if they were just simply determined by the shape of the sword they are coming from. 

I’m also wondering for the assymetrical ones, if there may be a "flexibility" to change the direction of the bur, making it usable as for the 90 degree one in both directions (pushing/pulling)?

I've been told the quality of steel during these times varied quite a lot. I assume we don't know have information regarding those scrapers?

This said as much as I'm curious to eventually try out with simple samples the double edges, thus using various types of steel to see how those function, I am more interested by the outlines (hence checking the measurements and proportions). As I’m more likely to for one bevel or a 90 degrees edge.

 

11 hours ago, Davide Sora said:

At this link you will find the scale drawings of Stradivari's tools made by Addie and hosted on Peter Grankulla's website. If you scroll to the bottom of the page you will find three printable PDFs for scrapers:

https://drive.google.com/drive/folders/1IIrVDvOC3-KS6YjwdrP9jmUvpdURcS08

The narrow and rounded ones seem to be double-beveled, and the others seem to be single-beveled, but I'm not 100% sure because I've never held them in my hand. In any case they have a single cutting edge.

 

[Ch. Dequincey]

17 hours ago, John Harte said:

From photos like the first below, I had assumed that these scrapers were double beveled.

The second photo features some of my scrapers made along similar lines.  These took a while to get used to but I have come to like how they work.

Thank you for sharing! May I ask what kind of steel you used for your set?

[Davide Sora]

34 minutes ago, Ch. Dequincey said:

Thank you for sharing! May I ask what kind of steel you used for your set?

Eberle Sweedish scraper steel, but I don't know the detail of that steel. Purchased in the 80s, now I don't know where to find them.

[John Harte]

3 hours ago, Ch. Dequincey said:

Thank you for sharing! May I ask what kind of steel you used for your set?

These were cut from power hacksaw blades which, according to the manufacturer, were made of M2 steel.  I had previously used this for small plane blades and found it worked well.

The edges of the scrapers shown in the photo are not turned; i.e., are a knife edge profile.  One benefit of this and the double bevel is being able to equally push or pull the scraper at similar angles relative to the work surface to achieve the same type of cut/scrape.

[Davide Sora]

On 12/2/2023 at 2:03 AM, Davide Sora said:

I have to ask the conservator to see them outside the box, so maybe I can also measure the thickness.

 

On 12/2/2023 at 4:01 AM, John Harte said:

 I look forward to hearing of what you discover if you do get to see them outside the box! 

Maybe adding weight to my best guess, old sword or knife tips would most likely be double beveled.  However a double bevel might not be so for all the scrapers.

I suspect that the scrapers are much thicker than the 1.6mm that I mostly used.  Stiffness was a consideration but creating an edge on thicker steel would have taken a lot longer...

Today I finally got to examine the Strad scrapers out of the box.
I took notes of the bevels, measurements, and thicknesses. In the image below I have indicated the lengths and thicknesses, taken with the caliper. I added some bevels that were missing from Addie's drawing, for example the pointed scrapers have the cutting edge even on the straight parts.

 

PS I reported the lengths because I noticed that in Addie's drawing (taken from photographs) there are some discrepancies in dimensions between the various scrapers. Nothing dramatic, just a few millimeters of difference. Even the shape of the thicker (4.2 mm) back scraper is not as asymmetrical as seen in the drawing, but is more symmetric.

[Davide Sora]

On 12/1/2023 at 2:43 PM, Ch. Dequincey said:

I’ve been looking at making scrapers based on those in the collection at the Violin Museum in Cremona  (MS 691 up to MS 697). To work out their outlines, I’m using the pictures and measurements provided by  the catalogue of their collection  . (https://museodelviolino.org/en/nuovo-libro-antonio-stradivari-disegni-modelli-forme/). 

During the process a few questions came up and I’m wondering if participants of this forum would have answers? 

1)While resizing the outlines to the measurements provided by the book, most of them worked pretty accurately besides the MS693 which seems slightly narrower when proportionally adjusted to length and most importantly the MS696 which is about 6mm longer when proportionally adjusted to the width measurements.  

As the book gives the exact same measures for the MS696 and the MS697, the latter fitting within the measurements provided.  

I’m wondering if it could be a mistake during the data recording/entry? Or a photo distortion that could have happened during the editing? Something else? 

(please ref to snapshot provided, the frame representing the size provided in the book). 

2) Has anyone had a chance to look at them out of their display box? And if so, have measurements of the MS696? 

3) Is there any record of their thickness available? 

4) Are there bevels on one side only or on both sides for each of them? 

 

Thank you for your insight,  

 

See my previous post.

[John Harte]

4 hours ago, Davide Sora said:

Today I finally got to examine the Strad scrapers out of the box.
I took notes of the bevels, measurements, and thicknesses. In the image below I have indicated the lengths and thicknesses, taken with the caliper. I added some bevels that were missing from Addie's drawing, for example the pointed scrapers have the cutting edge even on the straight parts.

Thank you Davide!  This is fantastic!!!

[Wood Butcher]

I know it is often mentioned that the Strad scrapers are made from sword blades, but looking at the dimensions and thicknesses provided by Davide, they could easily just be from old knives of various types.

[Davide Sora]

19 hours ago, Wood Butcher said:

I know it is often mentioned that the Strad scrapers are made from sword blades, but looking at the dimensions and thicknesses provided by Davide, they could easily just be from old knives of various types.

Yes, it is reasonable to think that they were made from knife blades and not swords, but saying swords or sabers is more fascinating.   I'm no expert on swords and sabers, and I have no idea how thick their blades were. The only scraper that looks like it was made from the tip of a sword is the long, narrow one for the back flutings of the scroll (I guess), which has a rhomboidal section and is very thick (4.2mm), while the others are less thick.

[Wood Butcher]

It is interesting, this one is so very thick. If this was a conscious choice, or just what was available will never be known. I have always found the Strad style pegbox fluting to be tricky to get right, a continuous radius is much easier to finish.

Looking at the scraper collection as a whole, the majority of them are significantly thicker than what most makers are using today. Despite them having ground edges, the scrapers would not flex much, if at all.

By comparison, I do the final scraping on my arching, using a sharp, thin and very flexible scraper, which I find follows the contours well, but this may just be me.

[Davide Sora]

3 hours ago, Wood Butcher said:

It is interesting, this one is so very thick. If this was a conscious choice, or just what was available will never be known. I have always found the Strad style pegbox fluting to be tricky to get right, a continuous radius is much easier to finish.

Looking at the scraper collection as a whole, the majority of them are significantly thicker than what most makers are using today. Despite them having ground edges, the scrapers would not flex much, if at all.

By comparison, I do the final scraping on my arching, using a sharp, thin and very flexible scraper, which I find follows the contours well, but this may just be me.

Yes, I can confirm that they are very stiff, definitely made to be used without flexing them.

[Ch. Dequincey]

On 12/21/2023 at 11:36 AM, Davide Sora said:

 

Today I finally got to examine the Strad scrapers out of the box.
I took notes of the bevels, measurements, and thicknesses. In the image below I have indicated the lengths and thicknesses, taken with the caliper. I added some bevels that were missing from Addie's drawing, for example the pointed scrapers have the cutting edge even on the straight parts.

 

PS I reported the lengths because I noticed that in Addie's drawing (taken from photographs) there are some discrepancies in dimensions between the various scrapers. Nothing dramatic, just a few millimeters of difference. Even the shape of the thicker (4.2 mm) back scraper is not as asymmetrical as seen in the drawing, but is more symmetric.

Thank you Davide (ad I am just catching up woth the thread now) this is going to be so useful!

[Davide Sora]

Just for the record, I discovered that the shape of Stradivari scrapers is suspiciously similar to those used by ceramists to make bowls, plates, and pottery. Especially the shape of the large ones, curved on one side and ending with a sharp point on the other, had always seemed uncomfortable to use in lutherie, I would not be comfortable at all with such a sharp point near my fingers and/or close to the wood, except that it wasn't used for the scroll, which however seemed too large to be comfortable for that task.

Possible options:
a) they were not used to make violins, but for pottery, although I don't know if Stradivari had a potter's hobby and I would tend to exclude this drastic hypothesis as they can also work very well for wood, therefore
b) they were scrapers normally made by blacksmiths for ceramists, an art much older and more consolidated than violin making, and purchased by violin makers because they were well suited to their purposes
c) Stradivari made these scrapers taking inspiration from those of ceramists, but adapting the dimensions to what he needed.

[Mark Norfleet]

Thank you Davide for taking the time to examine, measure and share what you learned about them with us.
it is very much appreciated! 

[Melvin Goldsmith]

Thank you Davide for your research and your valuable reflexive thoughts.

When I first saw the scrapers in real life at the Oxford Strad exhibition I was not convinced but my mind remains open. It is wonderful to have the information you provided.

The ceramicist and luthier are not dissimilar. Blade scrapers with an edge all way around cannot be used hard and fast shaping wood without cuts to hand in my opinion and experience.

If my workshop was to be historically dissected in 300 years time people might conclude that I was using a convection welder and fishing equipment to make violins!

Happy New Year!

[Davide Sora]

3 hours ago, Melvin Goldsmith said:

Thank you Davide for your research and your valuable reflexive thoughts.

When I first saw the scrapers in real life at the Oxford Strad exhibition I was not convinced but my mind remains open. It is wonderful to have the information you provided.

The ceramicist and luthier are not dissimilar. Blade scrapers with an edge all way around cannot be used hard and fast shaping wood without cuts to hand in my opinion and experience.

If my workshop was to be historically dissected in 300 years time people might conclude that I was using a convection welder and fishing equipment to make violins!

Happy New Year!

It has always been my concern too, how to use them without risking cutting your hands. Although I must admit that I have never tried to make copies to verify. I also have several tools lying around the workshop that I no longer use and if they were studied who knows what erroneous conclusions they would lead to.

However, I'm also convinced that they must have used something similar, they certainly didn't have the thin and flexible steel sheets that we have available today. I also think that tools such as scrapers, saws, planes, gouges, chisels, etc. would hardly have remained forgotten after the closure of Stradivari's workshop, more likely they would have been sold to general craftsmen who continued to use them. They were not as particular as the forms, drawings, and templates, which would only have been reusable by a luthier, who however would not have needed and paid money for them, as he already had his own.

 

[Davide Sora]

6 hours ago, Mark Norfleet said:

Thank you Davide for taking the time to examine, measure and share what you learned about them with us.
it is very much appreciated! 

 

3 hours ago, Melvin Goldsmith said:

Thank you Davide for your research and your valuable reflexive thoughts.

Happy New Year!

It's a pleasure to share these trivial things to let waste some time for you too.

Happy New Year!

[LCF]

9 hours ago, Davide Sora said:

Just for the record, I discovered that the shape of Stradivari scrapers is suspiciously similar to those used by ceramists to make bowls, plates, and pottery. Especially the shape of the large ones, curved on one side and ending with a sharp point on the other, had always seemed uncomfortable to use in lutherie, I would not be comfortable at all with such a sharp point near my fingers and/or close to the wood, except that it wasn't used for the scroll, which however seemed too large to be comfortable for that task.

Possible options:
a) they were not used to make violins, but for pottery, although I don't know if Stradivari had a potter's hobby and I would tend to exclude this drastic hypothesis as they can also work very well for wood, therefore
b) they were scrapers normally made by blacksmiths for ceramists, an art much older and more consolidated than violin making, and purchased by violin makers because they were well suited to their purposes
c) Stradivari made these scrapers taking inspiration from those of ceramists, but adapting the dimensions to what he needed.

A  forensic analysis might attempt to match striations on the wood surface of his violins with the details of the scraper edges.  

I don't know what the old Cremonese equivalent of the modern cardboard box or milk crate might have been but I can imagine that in the end days of a formerly busy workshop there would been boxes full of miscellanea in every dusty corner. The scrapers might have been in one of those - not very useful but too good to throw out.