Inside a Pietro Ruffini

[Tavy]

Another disassembled bowl for those that like images of bracing patterns

This one by Pietro Ruffini:



Fairly standard top and bracing, though heavily scalloped braces:



Flimsy bowl, no linings at all, braces inset into the sides with just a veneer thickness decoration over the top to hide them (which had subsequently crumbled away):



The most interesting thing was the "sandwich" construction of the fingerboard, with a only wafer thin MOP on the surface, it's going to pretty tricky to get this board leveled off once it's all back together:



And finally the cleaned up braces, in case anyone wants any bracing plans to copy:



In some ways this is a straightforward "collapsing top repair", in other ways it's going to be quite tricky to put back togther given how lightly built parts of it are.... could be interesting once it's done though....

Cheers, John.

[brunello97]

Great photos, John, thanks! I look forward to seeing more of the process. The top down shot of the braces is great. It gives a very graphic indication of the just how 'arched' these tops were.

Of interest to an ongoing conversation about constructing/slicing/joining halves of canted tops is your shot of the Ruffini top. Hard to tell from this angle, but it looks as if the grain run straight on one side of the seam and is tapered (as reflecting a cut on the other.) How does it look from where you are?

Mick

[Tavy]

Of interest to an ongoing conversation about constructing/slicing/joining halves of canted tops is your shot of the Ruffini top. Hard to tell from this angle, but it looks as if the grain run straight on one side of the seam and is tapered (as reflecting a cut on the other.) How does it look from where you are?

Hidden under clamps at present, will look later,

John.

[Tavy]

Of interest to an ongoing conversation about constructing/slicing/joining halves of canted tops is your shot of the Ruffini top. Hard to tell from this angle, but it looks as if the grain run straight on one side of the seam and is tapered (as reflecting a cut on the other.) How does it look from where you are?

I've looked several times and I can't decide if they took a slice out or not! The grain isn't straight and the two halves aren't bookmatched which makes it kind of hard to tell. If a slice was removed, it wasn't much for sure.

HTH, John.

[brunello97]

Thanks, John, for checking. I read with real interest the discussion here about the geometry of the two halves of a canted top relative to their joining and eventual induced curvature when fitted to a bowl. So now I keep an eye out for it. At work, I do a lot of 3D surface modeling using Rhino and the whole issue of double curvatures in materials is of interest.

I have only made one new top for a bowlback repair and that was for a mandola. It didn't remove a 'slice' before joining for a couple reasons. The original bowl profile itself was fairly flat--not much of a cant at at all. Also, the larger width of the top allowed for a bit more flex when fitting the top to the braces and bowl rim. I added a spruce support strip along the underside of the joint between the top halves. Should I do this again I would definitely look into slicing/shaping the profiles of the top halves.

I really enjoy following these 'bowlback repair' threads that you and Dave have been kind enough to provide. They are a pleasurable AM read and I always learn a lot.

Mick

[Tavy]

And finally...here it is all done - really the only tricky bit was getting the fretboard level - I had to lift the MOP from the first five frets, get the board almost level, re-insert the MOP into newly cut cavities, then finish leveling. Even then I couldn't get the board completely level - just the first 5 and last 5 frets, with a bit of a dip in the middle, so I had to cut some deeper than normal bar frets for "the dip", and that way I could get the frets all level at least. Plays nice, but with apologies to the owner, IMO sounds a touch weedy, probably down to the flimsy bowl

[Tavy]

Oops, hit the wrong button, and posted without the pics!

Here we go: