New hobby build

[olsk]

I have just started another guitar, which I am using as an opportunity to experiment with some new (to me) design ideas.

I am using a euro spruce top that is nicely quarter sawn, but does have some dark streaking down the center. I have decided to incorporate this into the design, so have shifted the soundhole to the upper bout, and will also add a soundport to make up for this.

This guitar will have indian rosewood back and sides, and a spanish cedar neck.

Jointing and joining the top plate:





The rosewood back:



Working on a rosette that will use a half circle of old mahogany and some bwb purfling:



Here you can see the streaking on the top:

[charles Tauber]

Two suggestions:

1. Avoid sharp corners, particularly as holes in the (highly stressed) top: sharp corners create stress concentrations leading to splitting.

2. Looking straight-on at the back (or front) of a guitar, the shape, generally, converges - larger at the bottom bout and smaller at the upper bout. Joining a piece of wood where the grain diverges - gets wider at the upper bout - fights the visual shape of the guitar. At least to my sense of aesthetics, you have the two things visually fighting each other to have the shape converge while the grain diverges. In the photo you've shown of the back, the drawn outline has the grain diverging: I'd have the outline flipped upside down from what is shown. With tops, I purposely trim tops so that the grain neither converges or diverges, but is parallel to the centre line. It's a small detail, but one that matters to me. It might not to you. There are many examples of guitars that are made contrary to the above, most of which, in my opinion, could have been improved by joining differently or locating the shape differently on the wood.

[mercy]

Agree with Charles on all points but of course its yours to do what you want.

[olsk]

Thanks for the advice Charles. I actually didn't plan how I would profile the back - at that point I had just been checking that the plate was large enough. I ended up flipping it





Here are the bent sides too. Still have to correct the spring back on the bending iron:



Here is a closer look at the finished soundhole / rosette.





I would hope that reinforcing the back of the design would be enough to negate any risk of splitting - what do you think?

Next up is bracing the plates and sorting the rims out.

Cheers,
Oli

[charles Tauber]

Originally Posted by olsk

Thanks for the advice Charles. I actually didn't plan how I would profile the back - at that point I had just been checking that the plate was large enough. I ended up flipping it

That looks nice.

I probably would have followed one grain line that runs the full length of the back, near the centre seam, then trimmed both halves to that line (sandwiched together), resulting in grain that runs parallel to the centre seam, rather than have the grain meet as a "V" along the centre seam.

I would hope that reinforcing the back of the design would be enough to negate any risk of splitting - what do you think?

A classical guitar style "donut" reinforcement on the interior would probably do it.

[runamuck]

I have yet to see Charles Tauber give bad or wrong advice.

[charles Tauber]

Originally Posted by runamuck

I have yet to see Charles Tauber give bad or wrong advice.

It's happened: you just haven't seen it.

[charles Tauber]

Olsk,

I like the bold soundhole/rosette approach you've taken. I'm curious about how it fits with the rest of the guitar details. Do you draw everything out full-size, do sketches or just develop it as it goes along?

For example, where does the end of the fingerboard lie in relation to the oblique line and where is the upper transverse brace relative to the sound hole? Does the angle of the black line have some significance in terms of the overall design and positioning of things? Ditto for the orientation of the grain of the mahogany.

[olsk]

A classical guitar style "donut" reinforcement on the interior would probably do it.

Great - that is what I was planning. I also feel adding stiffness around the soundhole helps get the tone I want. More focused.

I'm curious about how it fits with the rest of the guitar details. Do you draw everything out full-size, do sketches or just develop it as it goes along?

I really use a mixture of methods. I have built 2 guitars already in this body shape, so do have full size plans drawn out, and I have drawn an amended bracing scheme for this particular variation. I have simply angled the UT brace, and extended the neck block / fingerboard extension to add more stability.

For aesthetic design details - I like to improvise as I go along. I drew out that rosette and soundhole, but only when the time came to install it. I don't yet know how the headstock will look, for example.

I did consider having the fingerboard end at a matching angle. If it looks good to me then yes it would be a good way to have some consistent design elements. I feel like it might be crowded though, so might end up using a matching angle on the end of the headstock instead.

The main thing I want to get out of this build is understand if there is any worthwhile tone benefits to moving the soundhole and having more uninterrupted soundboard. Would be great to know how you think it will turn out!?