Router bits arent made to just cut a convex shape.
A CNC machine could make one though.
A CNC machine could make one though.
Yup... traditionally, and now, it was and is still done with gouges, chisels, scrapers. files and chalk. Time consumingQuite possible I'm missing something here, but I just woke up from a nap. Sounds to me that making a dimple with a router would work, but rather than routing a patch, seems like having it the right size and shape, just sanding the sides to fit it in would work. Then scrape it down as Tom suggests. Way back, when it was all done by hand, I'm sure there was a way of doing just what you want and by hand, I'd research that if it was me.
A crossgrain patch on the outside will stand out like a sore thumb. If this is a really expensive instrument that alone might reduce the value of the instrument. If it is on the inside, then you either have to dismantle the violin or find a way to go through the F holes. If you dismantle and repair, then the curve will be slightly inward (concave) so a convex bit would be a little more forgiving. But with a power tool, the slightest wobble will tear the instrument up. So I'm still suggesting you use a small hand plane, the kind that is used for guitars. The picture is a set of Ibex Violin Makers Planes.
I have also seen simple brass bodied planes about half an inch wide like the other picture. Not expensive. You could grind a convex curve into one of a set, concave in another and keep a third flat to smooth the patch. A plane wil let you go diagonally on the patch to smooth it out. But even with the miniature planes, I'd still create a clean edged shallow groove then cut the patch to that width laid in cross grain, then plane and then finish with a scraper. You can use a straight edge to guide the first plane so the edges are exact width. Since the patch grain is cross grain, it will bend into the groove so it will be pretty easy to plane flat to the surface of the area surrounding the patch. Finish leveling with a scraper, which will also give you a perfect surface you can't get with sanding.
One of my grand fathers made violins and repaired the instruments for the local schools for a living. I do know he made several of his own tools and that included several planes and scrapers of different kinds and sizes. Most of the planes and scrapers had curved blades, some convex and some concave.Quite possible I'm missing something here, but I just woke up from a nap. Sounds to me that making a dimple with a router would work, but rather than routing a patch, seems like having it the right size and shape, just sanding the sides to fit it in would work. Then scrape it down as Tom suggests. Way back, when it was all done by hand, I'm sure there was a way of doing just what you want and by hand, I'd research that if it was me.
OK, first off. What is your definition of time consuming? Hours? Days? What?Yup... traditionally, and now, it was and is still done with gouges, chisels, scrapers. files and chalk. Time consuming!
To make a new one, or to do this kind of repair. Most hand work takes time, but for things like this, it's the only way to go. Thin wood that is essentially carved to an exact shape and curve. I guess you could make a new violin that was passable with a CNC, but I don't think repairs could be done that way, at least affordably if it would even be possibly technologically.OK, first off. What is your definition of time consuming? Hours? Days? What?
I know a repair like that will take some time. I'm just wondering how much time it takes him to do it.To make a new one, or to do this kind of repair. Most hand work takes time, but for things like this, it's the only way to go.