Scoop and Corners

I thought this would be a simple issue, but as I started to think about it, it got more and more complex, because, as with many Cremonese practices, a lot of things are interconnected. One of the things I like about pondering Cremonese violin making is that most aspects are designed, not coincidence, so when you find a relationship it's usually meaningful—and relationships flow together throughout the whole violin.

In the case of purfling and edgework, it all starts from edge thickness. Almost invariably, the thickness of the unworn edge on a Cremonese violin (in the upper and lower bouts, excluding the corners and c-bouts, which are different issues) is equal to or slightly less than (allowing for finishing steps in the process) the distance from the edge to the purfling. This leads to the easy conclusion that the two are somehow related, and I think the relationship is clear: they were both set with the same tool. A single-bladed purfling cutter, such as the still-extant one of Stradivari, can do double duty: not only can it be used to cut the purfling groove; it also can serve to cut in from the side of a plate, to establish the finished edge thickness. I've done this, and of all the hand tool methods of finishing the edge thickness, it is by far the fastest and easiest.

(This method of working establishes a band of square cross-section edge outside the purfling, which begs to be rounded into a perfectly circular edge, that's not part of this discussion.)

Having located the position of the purfling, consider what happens at the corners, where the purfling lines meet from different directions. If you refer to the photograph, on the left side is a corner of one of my del Gesu model violins. This is a typical corner form for a 1735 or so instrument (later del Gesu corners differ from this in an number of ways). It's about 6.8mm across the end. The crest of the edge is about 1/3 of the way in, or a bit more, from the outer edge. The purfling meets a bit farther inside the end of the corner than a Strad would because though the del Gesu purfling is set in about the same distance from the edge, the corner is smaller at the end. These are the two critical factors in getting purfling to "work" at the corners—the width of the corner, and the inset of the purfling.

Look at the crest of the edge, as it approaches the corner from either direction. You can see that if the corner were narrower the two crests would meet, but as it is, they don't. This is an exaggerated illustration of what happens if you set the purfling too close to the edge, or make the corners too wide: the purfling never meets at the corner. If the purfling were 4mm in, and the corner 8mm wide at the end, the purfling point would be formed exactly at the end of the corner, and this isn't good, either. The end of the purfling joint should always be within the boundary of the crest on the end of the corner—in fact it shouldn't touch it at all (the bee-sting in my example is a bit on the long side—that period of del Gesu wouldn't really have one, so the point would be ever further from the end of the corner, normally, because of the small corner size of the del Gesu model), and this is why the largest Cremonese corner you'll ever see is about 7.5mm across the end. Many are smaller.

Stradivari and many of the other Amati school makers drifted the outer bout purfling inwards a bit as it approached the corner, and this caused the purfling joint to fall farther from the end of the corner than it natrually would, allowing them to extend the purfling for a bit of extra distance in an elegant bee-sting. I also think it allowed for a bit of wear on the outside side of the corner before it started to look ugly in its relationship to the purfling. Del Gesu didn't do this, and his purfling consequently looks a bit like it's been smashed together at the end in later examples, and usually follows the outside line of the corner more precisely. Makers from other cities often didn't think about any of this at all, and their purfling commonly does ugly things like running out the ends of their corners. Attention to all of the tiny details is one of the things that makes Cremonese violins so attractive and interesting.

Where all of this started was with the idea of explaining how the scoop of the edge is integrated into the corner shape. From the photo, on the left you can see that the scoop is limited at the outside by the crest around the edge (on the inside we don't have to worry about anything except blending it in with the arching, and attempting accuracy to the model we're following as regards the exact width and contour of the scoop). This crest continues around the end of the corner, and mimics the line of the corner itself, exactly. Since the scoop is quite wide and shallow, relative to the corner width, when it approaches the corner, there's a decision to be made: either the contour of the scoop has to become tighter (deeper and narrower) as it enters the corner, or the contour can stay the same, but it cannot remain at the same depth. The Cremonese approach used by Stradivari, and by del Gesu in the period for this corner, was to keep the same scoop, but make it shallower as it approached the end of the corner. That's what the photo on the right shows. The alternative, changing the scoop, results in a dug out sort of corner, lacking the elegance of the Cremonese solution.

Later del Gesus deal with this spot differently, in a method which is easier to accomplish, but which leaves a deep ugly trench at the end of the purfling. This usually has been attributed to the use of a shallow gouge cut made inward from the end of the point, but I believe the solution is actually much simpler, and sensible. Rather than attempting to scrape out his scoop in the edge beyond the purfling, I believe that later del Gesus are only gouged in this area and left raw. When the gouge marks coming from either direction meet over the tip of the purfling joint, the resulting junction is a surface that resembles the mark that would be left if a canoe were run aground there—a cut shaped like the prow of a boat, with a keel mark left in the wood bisecting the corner—the mark that others have mistaken for a gouge cut. At the moment I've got no photos prepared to illustrate this area, however.