Classical Edgework

Roger Hargrave 
Monday, November 7, 1988, 3:30 p. m.

My talk this afternoon is a kind of continuation of my lecture this on morning on the Cremonese method of construction. I am often asked why I spend so much time making precise copies of classical instruments, trying to reproduce every wobble, bulge and tool mark exactly as the master did, even when they appear to be a slip of the hand. The stock-in-trade answer is that Raphael copied the works of Michelangelo Buonarroti in order to achieve a better understanding of them, and I copy the works of the great violin makers for the same reason.

But then comes the retort: Why is it necessary to artificially wear the instruments if this is your only consideration? I must confess that I have always found this particular question difficult. Naturally, I do have good reasons, but they are complex and sometimes seem, even to me, irrational and unreasonable. Moreover, until recently, it has always been a problem to pinpoint the precise knowledge which I have gained from such actions.

The following talk, then, is something of a justification for my copy work, which is really only an extension of my previous work as a restorer. If I had not tried to achieve the effect of worn classical edges, I would never have thought about the possibilities of working the edges in a different way. This talk also latches on to my earlier talk about baroque construction, and to some extent it contradicts my earlier article in The Strad magazine. But I think this theory, apart from being more radical, is probably also more accurate.

Stradivari's edgework is very distinctive and it is also extremely difficult to reproduce with any semblance of accuracy. Whereas many Strad copyists manage to capture the spirit of his sound holes, the purfling and even to some extent his heads and archings, Strad's edgework usually defeats most copyists. This is because in order to reproduce such features, it is often not enough simply to know what they look like; it is also necessary to know why they look the way they do.

Among the points a connoisseur will be looking for when eyeballing a prospective Strad is the tendency for the edgework, when viewed from the side, to be slightly thicker in the center bouts than it is in the upper and lower bouts and also for the corners to be slightly thicker (Fig. 1). This feature of the edgework is usually interpreted as being the result of Stradivari's pursuit of an optical balance. I want to apologize for the drawings you will see projected on the screen. As I said this morning, I am a failed artist.

The theory states that because the edgework, when viewed from the side, is closer to the eye in the upper and lower bouts, the center bout edges were made thicker to compensate; unfortunately it doesn't. Meanwhile, the corners were made even stronger than the edgework in order to give them visual impact, thus adding elegance to otherwise plain parallel lines. This is a nice theory, because it drops neatly into all that ethereal stuff about Greek temples, the golden section, swelling columns, et al.: I often think that this is very much a connoisseur's theory. The idea that these features might be the result of very specific working practices came to me only recently, when I was commissioned to make a copy of a G. B. Guadagnini violin. Although there is an increase in the thickness of the edgework in the center bouts of Guadagnini's instruments, the corners become strangely thinner, tapering off towards the end (Fig. 2).

At the same time, however, the thickness of the edgework increases dramatically as it nears the button, and the button itself is thicker (Fig. 3).

With the Guadagnini copy I found the subtleties of the edge difficult to reproduce, until I hit upon the idea of cutting the purfling channel right to the outside edge of the plate, before rounding it off in the usual way. I made the plate a little thicker and cut the channel down. I then rounded the plate and let the channel half run right out to the edge (Fig. 4). It should be noted that the process of rounding an edge which has been channelled to the outside outline effectively decreases the thickness of the edge. For this reason the edges of the plates needed to be thicker in the first place. The drawing is a slight exaggeration: the thickness of the plates required is not quite as much as this drawing indicates. Most modem makers set the various heights of the edges and then work their channeling to a point about 1/3 to 1/2 way between the line of the purfling and the outside of the plate.

By running the channel out to the edge on my Guadagnini copy I found, on reaching the corners, that the channels could simply run out of the ends where the two gouge cuts met, rather like the fluting on a Stradivari sound hole wing (Fig. 5).

When the corners were then rounded off, the process of removing the deep scoop running out of the end automatically produced a thin tapering comer in the Guadagnini style. In the drawing, you can see the gouge cut coming down to the corner and the line indicating where the next gouge cut will be made. The gouge strokes run right out to the end of the corner. This is because at the corner the full depth of the channel had to be removed by the rounding off process, whereas as Figure 6 indicates, only a part of the side of the channel was removed when the edges were being turned. At the left of the drawing you can see the curve at the edge; at the right you can see the full depth of the corner.

At the button, Guadagnini realized that Strad's channeling ran well inside the projected line of the outline; and in order to comply with what he saw on Strad's buttons, he simply swung the channel away from the outside edge as it passed the button area (Fig. 7). Here the effect on rounding the edge was to leave the button and the adjacent edgework slightly thicker, as I showed you on an earlier drawing. This was not then, as I and many others had previously thought, a conscious effort by Guadagnini to strengthen the button. But as we shall see later, it was a by-product either of not having understood Stradivari's ideas, or not having the time, energy or will to interpret them to the full.

The idea that Stradivari and the other classical Cremonese makers worked their channeling to the outside edge actually makes a great deal of sense. Stradivari and his contemporaries, however, were concerned that their corners should not be tapered toward the ends. But in order to compensate for the channeling running out at the corner ends, they needed to make their corners much thicker than the remaining edgework from the start and at the finish. Altogether I reckon they started with a corner thickness of 5.25 mm for a violin in order to arrive at a final thickness of about 4 plus. It turns out to be a beautifully simple way of finishing the corners because the hollowing did not need to be carefully worked with a scraper back to a hollow squared end as with the modern method. Stradivari's edgework and corner ends were simply turned back until the squared hollow formed itself. Incidentally, this also ex-plains how the impossibly deep incised corners of some Guarneris were created. They were deeply incised with a gouge and the corners were then worked back and left tremendously deep. This is almost impossible to copy unless you do it the same way.

The reason why Stradivari's center bout edgework turned out thicker than that of the upper and lower bouts is a little more complicated to explain (Fig. 8). It has to do with the different types of curves required for the channeling and how they relate to the different cross-arching curves. The probability is that he used differ-ent gouges for these different curves. Clearly, the center bout channel was tighter than that of the remaining edgework. Now, in order to keep the thickness of the edge constant at the deepest point of the channel, marked with an A, all around the instrument (i.e., the line of the purfling) whilst using curves of a different radius, the tighter center bout curve requires a thicker edge, otherwise it will not meet the rounding off chamfer at the same distance from the outline. The tighter curve is that of the C bout; the flatter curve is that of the outer bouts.

Keeping the same edge heights in the center bouts would have meant that the tighter curve of the channel would have had to be worked deeper, resulting in a weakness of the plate at the edges (Fig. 9). G. B. Guadagnini probably copied the extra thicknesses in the center bouts, because he knew that it was necessary to have strength at this point. He probably did not copy the corners because it was not a structural necessity.

Keeping in mind that both Stradivari and Guadagnini started with a thicker edge than they would eventually end up with, we now turn to the button (Fig. 10).

Here Stradivari continued his channeling across the area of the button as if he were still following the outline. He then turned his edge back in the usual way, leaving the button proud (Fig. 11).

Later, in order to achieve what we recognize as the classical button-channel relationship, he worked the button down to the new "meeting point" of the edge and channel. This process left the button wedge shaped, and this wedge shape is a feature of all clean Stradivaris. The most striking example which I can think of is the "Medici" tenor viola in Florence, on which the button tapers almost 1.5 mm from the channel to the tip.

We are now confronted with the more difficult question: At what stage in the making process was the edgework itself finished? When I wrote the article on baroque construction, first published in The Strad magazine a couple of years ago now, I was leaning towards the opinion that the plates were completely finished-edgework purfling and all-before they were finally attached to the ribs. I am now of the opinion that this was not the case. I have prepared a series of diagrams describing the process which I now believe comes closer to the original method. In Figure 12 we can see part of the cross-section of a belly arch taken above the sound holes. (Actually, loosely based on the "Betts" Stradivari of 1704.) At this stage the outline has been prepared and finalized as I described the process in my previous talk this morning.

Most of the arching has been finished, but it runs out to a flat platform similar to that described by Sacconi. In this case, however, the platform is much thicker (by approximately 1.25 to 1.5 mm) than the finished edge will eventually be. This is only an estimate; I can't tell you exactly how thick to make it at the moment. I've made several instruments using this method and I am still working to arrive at the exact edge thickness. We can see how the plate has been hollowed in the usual way, but before the plate is finally glued to the ribs, a knife-cut chamfer was made to the underside of the edgework. This chamfer is a typical Cremonese feature. It was made to facilitate an easy rounding of the edge after the plates had been permanently fixed to the ribs.

Having examined hundreds of these knife-cut chamfers, I do not believe that they were ever made after the body had been closed. The urgency of the cut and some of the angles, especially in the tighter curves of the center bouts, would lead me to expect to see knife marks on the ribs themselves. Even on the most expressive Cremonese works, this is not the case. You will not find any knife marks. However, knife marks are extremely common on the inside of the ribs, where the linings have been cut back. Therefore, because I have never seen knife marks on the ribs I must assume that the ribs were not attached when these chamfers were cut.

The bottom of Figure 12 shows the closing of the body, the plates being permanently attached to the ribs. This was most probably done before the purfling itself was inlaid. This makes good sense, because even with quite primitive closing clamps there was no danger of damaging or breaking off the edgework.

The next stage remains somewhat ambiguous (Fig. 13). Was the purfling simply inlaid into a trough cut into the platform before the channel was cut, or was the channeling finished and the purfling inlaid into the bottom afterwards? Although I can find few reasons to support the first theory, it cannot be ruled out as a possibility. In support of the second theory that the channel was cut first before the trough for the purfling, there are a number of points. First, there are the traces of the purfling marker which are often visible in the corners. If the channel had been cut after the purfling had been inlaid, then we would expect these marks would have been removed in the process. Second, the scribe lines often seen at the high point of unworn edges, often visible on classical instruments, are more likely to have remained intact if they were made after the channel had been cut. This is because the maker would have worked up to the scribe line from one side only and not from both sides, as is the case with the modern method. This is, however, by no means a conclusive argument. Third, it would quite obviously have been much easier to cut the purfling trough into the bottom of a channel rather than to incise it deeply into a thick and, in this case, an extra thick flat platform. We should especially take into account that the plates were attached to the ribs at this stage and not on the bench, where more pressure can be applied to the knife in cutting a very deep channel. Finally, if we look at the decorated instruments, we can see that it would not have been possible to cut back with a gouge the ivory lozenges and diamonds as part of the channel-forming process.

Obviously, some final scraping up of the purfling channel would have been essential in order to remove any black filler, which Strad commonly used, or traces of glue, and generally to clean up the purfling itself. This would have all been done at the same time as the channel was being blended into the arching proper. On the belly, the sound hole wings would also have been fluted at the same time. Figure 13 shows the rounding and lowering of the edgework to the finished height. The button would have been finished last.

That is basically what I wanted to say.Roger Hargrave

Monday, November 7, 1988, 3:30 p. m.

My talk this afternoon is a kind of continuation of my lecture this on morning on the Cremonese method of construction. I am often asked why I spend so much time making precise copies of classical instruments, trying to reproduce every wobble, bulge and tool mark exactly as the master did, even when they appear to be a slip of the hand. The stock-in-trade answer is that Raphael copied the works of Michelangelo Buonarroti in order to achieve a better understanding of them, and I copy the works of the great violin makers for the same reason.

But then comes the retort: Why is it necessary to artificially wear the instruments if this is your only consideration? I must confess that I have always found this particular question difficult. Naturally, I do have good reasons, but they are complex and sometimes seem, even to me, irrational and unreasonable. Moreover, until recently, it has always been a problem to pinpoint the precise knowledge which I have gained from such actions.

The following talk, then, is something of a justification for my copy work, which is really only an extension of my previous work as a restorer. If I had not tried to achieve the effect of worn classical edges, I would never have thought about the possibilities of working the edges in a different way. This talk also latches on to my earlier talk about baroque construction, and to some extent it contradicts my earlier article in The Strad magazine. But I think this theory, apart from being more radical, is probably also more accurate.

Stradivari's edgework is very distinctive and it is also extremely difficult to reproduce with any semblance of accuracy. Whereas many Strad copyists manage to capture the spirit of his sound holes, the purfling and even to some extent his heads and archings, Strad's edgework usually defeats most copyists. This is because in order to reproduce such features, it is often not enough simply to know what they look like; it is also necessary to know why they look the way they do.

Among the points a connoisseur will be looking for when eyeballing a prospective Strad is the tendency for the edgework, when viewed from the side, to be slightly thicker in the center bouts than it is in the upper and lower bouts and also for the corners to be slightly thicker (Fig. 1). This feature of the edgework is usually interpreted as being the result of Stradivari's pursuit of an optical balance. I want to apologize for the drawings you will see projected on the screen. As I said this morning, I am a failed artist.

The theory states that because the edgework, when viewed from the side, is closer to the eye in the upper and lower bouts, the center bout edges were made thicker to compensate; unfortunately it doesn't. Meanwhile, the corners were made even stronger than the edgework in order to give them visual impact, thus adding elegance to otherwise plain parallel lines. This is a nice theory, because it drops neatly into all that ethereal stuff about Greek temples, the golden section, swelling columns, et al.: I often think that this is very much a connoisseur's theory. The idea that these features might be the result of very specific working practices came to me only recently, when I was commissioned to make a copy of a G. B. Guadagnini violin. Although there is an increase in the thickness of the edgework in the center bouts of Guadagnini's instruments, the corners become strangely thinner, tapering off towards the end (Fig. 2). At the same time, however, the thickness of the edgework increases dramatically as it nears the button, and the button itself is thicker (Fig. 3).

With the Guadagnini copy I found the subtleties of the edge difficult to reproduce, until I hit upon the idea of cutting the purfling channel right to the outside edge of the plate, before rounding it off in the usual way. I made the plate a little thicker and cut the channel down. I then rounded the plate and let the channel half run right out to the edge (Fig. 4). It should be noted that the process of rounding an edge which has been channelled to the outside outline effectively decreases the thickness of the edge. For this reason the edges of the plates needed to be thicker in the first place. The drawing is a slight exaggeration: the thickness of the plates required is not quite as much as this drawing indicates. Most modem makers set the various heights of the edges and then work their channeling to a point about 1/3 to 1/2 way between the line of the purfling and the outside of the plate.

By running the channel out to the edge on my Guadagnini copy I found, on reaching the corners, that the channels could simply run out of the ends where the two gouge cuts met, rather like the fluting on a Stradivari sound hole wing (Fig. 5). When the corners were then rounded off, the process of removing the deep scoop running out of the end automatically produced a thin tapering comer in the Guadagnini style. In the drawing, you can see the gouge cut coming down to the corner and the line indicating where the next gouge cut will be made. The gouge strokes run right out to the end of the corner. This is because at the corner the full depth of the channel had to be removed by the rounding off process, whereas as Figure 6 indicates, only a part of the side of the channel was removed when the edges were being turned. At the left of the drawing you can see the curve at the edge; at the right you can see the full depth of the corner.

At the button, Guadagnini realized that Strad's channeling ran well inside the projected line of the outline; and in order to comply with what he saw on Strad's buttons, he simply swung the channel away from the outside edge as it passed the button area (Fig. 7). Here the effect on rounding the edge was to leave the button and the adjacent edgework slightly thicker, as I showed you on an earlier drawing. This was not then, as I and many others had previously thought, a conscious effort by Guadagnini to strengthen the button. But as we shall see later, it was a by-product either of not having understood Stradivari's ideas, or not having the time, energy or will to interpret them to the full.

The idea that Stradivari and the other classical Cremonese makers worked their channeling to the outside edge actually makes a great deal of sense. Stradivari and his contemporaries, however, were concerned that their corners should not be tapered toward the ends. But in order to compensate for the channeling running out at the corner ends, they needed to make their corners much thicker than the remaining edgework from the start and at the finish. Altogether I reckon they started with a corner thickness of 5.25 mm for a violin in order to arrive at a final thickness of about 4 plus. It turns out to be a beautifully simple way of finishing the corners because the hollowing did not need to be carefully worked with a scraper back to a hollow squared end as with the modern method. Stradivari's edgework and corner ends were simply turned back until the squared hollow formed itself. Incidentally, this also ex-plains how the impossibly deep incised corners of some Guarneris were created. They were deeply incised with a gouge and the corners were then worked back and left tremendously deep. This is almost impossible to copy unless you do it the same way.

The reason why Stradivari's center bout edgework turned out thicker than that of the upper and lower bouts is a little more complicated to explain (Fig. 8). It has to do with the different types of curves required for the channeling and how they relate to the different cross-arching curves. The probability is that he used differ-ent gouges for these different curves. Clearly, the center bout channel was tighter than that of the remaining edgework. Now, in order to keep the thickness of the edge constant at the deepest point of the channel, marked with an A, all around the instrument (i.e., the line of the purfling) whilst using curves of a different radius, the tighter center bout curve requires a thicker edge, otherwise it will not meet the rounding off chamfer at the same distance from the outline. The tighter curve is that of the C bout; the flatter curve is that of the outer bouts.

Keeping the same edge heights in the center bouts would have meant that the tighter curve of the channel would have had to be worked deeper, resulting in a weakness of the plate at the edges (Fig. 9). G. B. Guadagnini probably copied the extra thicknesses in the center bouts, because he knew that it was necessary to have strength at this point. He probably did not copy the corners because it was not a structural necessity.

Keeping in mind that both Stradivari and Guadagnini started with a thicker edge than they would eventually end up with, we now turn to the button (Fig. 10). Here Stradivari continued his channeling across the area of the button as if he were still following the outline. He then turned his edge back in the usual way, leaving the button proud (Fig. 11). Later, in order to achieve what we recognize as the classical button-channel relationship, he worked the button down to the new "meeting point" of the edge and channel. This process left the button wedge shaped, and this wedge shape is a feature of all clean Stradivaris. The most striking example which I can think of is the "Medici" tenor viola in Florence, on which the button tapers almost 1.5 mm from the channel to the tip.

We are now confronted with the more difficult question: At what stage in the making process was the edgework itself finished? When I wrote the article on baroque construction, first published in The Strad magazine a couple of years ago now, I was leaning towards the opinion that the plates were completely finished-edgework purfling and all-before they were finally attached to the ribs. I am now of the opinion that this was not the case. I have prepared a series of diagrams describing the process which I now believe comes closer to the original method. In Figure 12 we can see part of the cross-section of a belly arch taken above the sound holes. (Actually, loosely based on the "Betts" Stradivari of 1704.) At this stage the outline has been prepared and finalized as I described the process in my previous talk this morning.

Most of the arching has been finished, but it runs out to a flat platform similar to that described by Sacconi. In this case, however, the platform is much thicker (by approximately 1.25 to 1.5 mm) than the finished edge will eventually be. This is only an estimate; I can't tell you exactly how thick to make it at the moment. I've made several instruments using this method and I am still working to arrive at the exact edge thickness. We can see how the plate has been hollowed in the usual way, but before the plate is finally glued to the ribs, a knife-cut chamfer was made to the underside of the edgework. This chamfer is a typical Cremonese feature. It was made to facilitate an easy rounding of the edge after the plates had been permanently fixed to the ribs.

Having examined hundreds of these knife-cut chamfers, I do not believe that they were ever made after the body had been closed. The urgency of the cut and some of the angles, especially in the tighter curves of the center bouts, would lead me to expect to see knife marks on the ribs themselves. Even on the most expressive Cremonese works, this is not the case. You will not find any knife marks. However, knife marks are extremely common on the inside of the ribs, where the linings have been cut back. Therefore, because I have never seen knife marks on the ribs I must assume that the ribs were not attached when these chamfers were cut.

The bottom of Figure 12 shows the closing of the body, the plates being permanently attached to the ribs. This was most probably done before the purfling itself was inlaid. This makes good sense, because even with quite primitive closing clamps there was no danger of damaging or breaking off the edgework.

The next stage remains somewhat ambiguous (Fig. 13). Was the purfling simply inlaid into a trough cut into the platform before the channel was cut, or was the channeling finished and the purfling inlaid into the bottom afterwards? Although I can find few reasons to support the first theory, it cannot be ruled out as a possibility. In support of the second theory that the channel was cut first before the trough for the purfling, there are a number of points. First, there are the traces of the purfling marker which are often visible in the corners. If the channel had been cut after the purfling had been inlaid, then we would expect these marks would have been removed in the process. Second, the scribe lines often seen at the high point of unworn edges, often visible on classical instruments, are more likely to have remained intact if they were made after the channel had been cut. This is because the maker would have worked up to the scribe line from one side only and not from both sides, as is the case with the modern method. This is, however, by no means a conclusive argument. Third, it would quite obviously have been much easier to cut the purfling trough into the bottom of a channel rather than to incise it deeply into a thick and, in this case, an extra thick flat platform. We should especially take into account that the plates were attached to the ribs at this stage and not on the bench, where more pressure can be applied to the knife in cutting a very deep channel. Finally, if we look at the decorated instruments, we can see that it would not have been possible to cut back with a gouge the ivory lozenges and diamonds as part of the channel-forming process.

Obviously, some final scraping up of the purfling channel would have been essential in order to remove any black filler, which Strad commonly used, or traces of glue, and generally to clean up the purfling itself. This would have all been done at the same time as the channel was being blended into the arching proper. On the belly, the sound hole wings would also have been fluted at the same time. Figure 13 shows the rounding and lowering of the edgework to the finished height. The button would have been finished last.

That is basically what I wanted to say.