The Double Florentine Cutaway

Hello, amateur guy here. For some reason I decided to do a double Florentine cutaway. I think I was inspired by some stuff Jerry Hoffmann has posted. You know, the guy that does the exquisite super clean stuff (Hluth). My research showed me that a Venetian cutaway would be a lot easier, but I like the look of the Florentine. I actually think that a cutaway on a uke doesn't make any sense from a players point of view, but I think it looks cool so why not? Just having some fun in the uke shop.

The concept is simple: Bend sides as usual and then cut out the sides and reverse the upper bout. Convex becomes concave. Cut absolutely plumb to the sides, brace, reinforce and go. What could be simpler... Ha ha ha!

The plumb cut was simple, but immediately I was in the weeds when I sanded down for a flush joint. The angle is impossible to calculate and every thing needs to be plumb. After I figured that out, I noticed that the joint is very weak and needs to be seriously reinforced. After gluing in struts and cleats I realized I had bitten off way more than I can chew. I hope I can pull this off, but lord, what a puzzle. The thing that bothers me is that the joint is inherently weak. I'll get it, but do not try this at home unless you have a lot of time to waste.

I built a simple form instead of using a mold to see the reveal in the joint. Anyway, things get genuinely weird quickly. I finally got the thing beat, but what a struggle.

That's a very interesting shape! I like it. I did a 3/4 size guitar with a double cutaway a couple of years ago. It is certainly a massive amount of extra work, especially if you decide to bind the corners!
I can't quite make it out from the pictures, but it looks like you butted the two side pieces up to each other with a strip of wood in between. I'm afraid this will make for a weak joint, as you say. The normal way of doing it is to split the angle the sides make to each other and sand this into the edge, if that makes sense. It then gets reinforced by a block on the inside, shaped to the exact angle.
I also reinforced the upper bout with carbon buttress braces, but this was a steel 6 string, so way more tension than a uke.

This is how I glued up the corners. You can use the offcuts from the corner blocks as the outer cauls.

Nice looking guitar. I like the way the knots in the wood add to the look without being "flaws"... Anyway, here is where I started off wrong. Make the reinforcing corner braces first and then make the sides conform to them rather than the other way around by trying to make the brace conform to the angle of the sides. Too late now! It will be OK in the end after a lot of futzing and this is just an experimental fun side project while I work on more conventional ukes. Ask me if I'm still having fun when it comes time to bind the thing. I can see already some potential issues here. By the way, here at the F. Flintstone School of Lutherie we don't have problems, we only have "issues". Ha! Yeah right.

Later on, if you like, you could do a similar build with a bigger support block on the inside, flatten the cutaway from the outside, add a matching or contrasting block on the outside, then round it into a very tight Venetian cutaway. Its a lot easier than trying to bend one that tight.

Yes, there needs to be a big support block in there. Since the joint is obviously unstable, I spent the better part of this afternoon over bracing it. I used bits and pieces of cut off maple bindings that I saved (curly! Never throw anything away!) to build up a sort of "glu-lam" brace system for the joints. Interestingly and counter intuitively, this is actually stronger than a single monolithic brace. However, the amount of labor involved is ridiculous. Basically I cranked up the baseball game on the radio and spent hours gluing in in little splints of wood. Kind of fun actually, but I'm never doing this again. The joints are finally stable enough that I trust them.

Actually I think the Venetian cutaway would be easier. All it entails is a sharp bend (not that hard to do). The difference is that the Venetian is a single continuous piece of stable wood and the Florentine cuts that wood and is inherently unstable. I like the look of the Florentine, but will probably never attempt it again. It is just a weak design if you ask me. Pictures below of the "glu-lam" braces. It will all be cleaned up of course and look fine in the end once things are trimmed down. This is the raw view. Note how I had to tie off the upper joint off to the neck block. Absolutely essential. What a pain. Definitely a big Boy Scout Project.

That's the coolest side sound port idea I have ever seen.

little timber said:

That's the coolest side sound port idea I have ever seen.

Click to expand...

Thanks! I'm guessing you meant my guitar btw, seeing as Sequoia's doesn't have a side port. It wasn't actually my idea - I copied it from Michi Matsuda.
Sorry, I don't mean to hijack the thread.

This looks like a difficult en-devour, but I really think it's a cool looking design. You might have started a new fad!

It made me immediately think of his guitars, wonderfully done!