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I'm in the midst of drafting my first guitar. I've built others, but this is my first attempt at an original design. The dimensions are nearly the same as a Dreadnought, but the curves are quite a bit different. I'm partial to more of a sloped shoulder, but also wanted a tighter waste curve. It's more along the lines of a SJ than a D. Opinions welcome, aesthetics, design, or otherwise.

Mitch

How's 'bout some dimensions or a sketch?

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Don't confront me with my failures--I have not forgotten them.

Sorry, the picture didn't attach and my computer froze 3 times in the process of resizing it .

Dimensions

11 3/8 at upper bout
9 1/4 at waist
16 at lower bout
20" long

I'm working on a similar shape -- a D-influenced SJ, or v.v., mostly for ergonomics. After 6 iterations, I'm at a 10.0" waist, 15.6" lower bout, 11.2" upper bout, 20.25" length, slope shoulder, 3" radii at the waist and shoulders, with 13 frets to the body.
- I tried to keep the lower bout fairly wide (= Martin D), but I see Taylor's GA and Larrivee's L-03/6/9 are the full 16", so 15.6" may not have a truly full bass. But I'm going to try to work with it as I'd like something easier to hold.
- To make up for potential loss of bass, I stretched the length a bit and put the bridge lower on the lower bout (13 fret), which pulled the X down, too (but it's still ~high).
- With 3" radii, I couldn't get the waist any tighter than 10.0" without it looking goofy, or having a tiny upper bout. We use a simplified side-bending technique (this is for student projects), and it's risky for us to go tighter than 3". But then I find smaller radii than that don't seem to sit fully down on the leg anyway.
- Overall, mine is looking kinda like a Seagull.

(didn't see your 2nd post until posting this)

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David Malicky

What I like to do when I'm working on a new shape is to draw in the bridge, rosette and fingerboard extension to get an idea of what it will all look like as a whole. It's amazing how subtle changes make a big difference in how the shape looks. I think what you have will make a nice sounding guitar. You might want to refine the lines where the waist transitions to the upper bout, but otherwise I think it looks good. Of course there is no substitute for seeing it in 3D.

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Ken Franklin
clumsy yet persistent
https://www.kenfranklinukulele.com

I started a new design based on a Stahl last year, and after 5 instruments I'm still making little tweeks. Here's a shot of 3 showing small changes.

Still tweeking the mould, but getting closer...
I would agree with Ken, nothing like seeing it in it's finished form. I won't presume to critique your design, as your taste may differ quite a bit from mine, however I will say don't be in a rush. Make revisions in the drawing and hang it on a wall for a week and stare at it.

Kinda like this? I think the radius of the waist is tighter than 3" though. The lower bout is 15 1/2" ish. I'll have to measure it and check all the dimensions.

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I didn't mean to say it, but I meant what I said.
http://www.brackettinstruments.com/

I like it a lot, I think it's a nice shape. Nice work!

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http://www.PeakeGuitars.com

Thanks everyone who gave suggestions and input. It was back to the drawing board last night and this morning and here's a shot of what I came up with. The one half was from my original template (the same that was posted before), and the other half almost turned into more of an MJ?. The lower bout and length are the same, but the radius of the waist is now at about 2 3/4 and 5" wide (10" total). I also made the upper bout to 12" and re drew the curve a bit. And after Ken's suggestion I drew in the fretboard and sketched in a pseudo rosette and bridge both in there correct locations.

Thanks again to everyone who has already weighed in on this!
Hanns those are some great looking guitars. It's a very classy design.

Woody that's real close to what I had in mind. Do you have a flat at the tail block or is that radiused the whole way?

The tail block is flat, but the curve starts real close to the edge of the block. IME it's easier that way.

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I didn't mean to say it, but I meant what I said.
http://www.brackettinstruments.com/

What scale are you shooting for, and is it 12 or 14 fret neck? I'd put the
bridge a bit more towards the center of the lower bout, and I'd also round
the bottom of the lower bout more, to help with the vibration modes of
the top.

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Gene

Politicians and diapers must be changed often, and for the same reason- Mark Twain

I like those adjustments, Mitch. What do you think? As Haans says you have to be the judge of what looks best to you. Having it hang on the wall for awhile is a good thing too. If you have an adjustable building form you can even tweek the shape a little before you install the back and top.

As to bridge placement, your scale length and number of frets to the body will determine that. What you have now looks about right for a 25.4 scale 14 fret guitar, but I've made some guitars with the bridge more in the middle of the lower bout as Gene suggests. They were 13 fret guitars and the bridge placement seemed to favor a sweeter sound.

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Ken Franklin
clumsy yet persistent
https://www.kenfranklinukulele.com

Nice design... I especially like the upper bout of the new design, with the sloped shoulder. Personally, I like a little smaller flat spot at the tail (symmetry w/ sloped shoulder) but Haans' have flat tails and his are very elegant. Also, not sure if it's a character feature or not, but I think the curve could be slightly smoother about 4" below the waist (on new design). Attached is where I'm at currently, if helpful. I agree with Haans and Ken, that looking at it over the span of days or weeks helps refine it. There's an interesting decision on a narrower waist design with the X brace angle and placement, but that's for another thread.

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David Malicky

Thanks David. Your drawing does help. I wasn't very happy with the connection of the lower bout and waist, but I can't quite see it in my head exactly how I want it. I'm gonna take some time away from it and come back in a couple days and maybe I'll be able to make the refinements to bring it together to something I'm happy with. I will definately post pictures as I feel better about it. As it's drawn now, it's a 14 fret 25.4 scale length with 21frets just because I took some thought of the placement of the upper transverse brace and where I wanted it and the soundhole location. I hadn't considered a 13 fret, which would make it 20 frets at about the same SH location and would also help to put the bridge back a little bit. That would take both Gene and Ken's suggestions into account. I have been using an x brace design with 3 tone bars on a j 45 body shape. The only one that I have completed had a cedar top, but I have a sitka top braced and voiced, ready to be boxed up. I'm going to try and incorporate the 3 tone bars into this design and just see how it turns out and tweak from there. I'll also post pictures of the brace layout when I have it put on. If this Sitka J 45 comes out sounding confined I might reconsider my bracing and save the 3 tone bars for cedar tops. So much to experiment with....This is what keeps me going!

Mitch, make sure you draw both sides out of any changes you make. Paper is cheap compared to a couple of sheets of baltic birch.
David, none of the instruments have flat tails, but I have been varying the amount of curve at the tail and nose blocks to get it "just right". Here's a shot of a 6 string that has just a bit to much curve at the endblock...

What about the shape of the D-18. It has sloped shoulders and a very nice shape. It is a 12 fret which brings your bridge lower into the "sweet spot"

What about the shape of the D-18. It has sloped shoulders and a very nice shape. It is a 12 fret which brings your bridge lower into the "sweet spot"

What about the shape of the D-18. It has sloped shoulders and a very nice shape. It is a 12 fret which brings your bridge lower into the "sweet spot"

Haans,

Your "too much curve" is my just right. I guess I'm saying it's a personal preference. It looks a bit more modern in my opinion. Did you have a reason for preferring it flatter? It appears you were trying to emulate an older design, right?

Kent

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Kent

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Haans,
I agree with Kent, I like curvy butts That didn't come out right...but I do like the look of a more rounded bottom(that didn't sound right either )

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Tracy
http://www.luthiersuppliers.com

Gene,

Would you mind elaborating how the roundness of the lower bout affects the top's vibration nodes? I would sure like to learn more on that subject.

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Formerly known as Adaboy.......

Well, I like that "hourglass figure" myself, but as you all know, bottoms come in all kinds of shapes...
The instrument shape started out as a Stahl 15" (Larson), but I've made many changes, and am still trying to find the exact shape I like. The 6 is just a little too round for me, I kinda like the shape of 12 on the right best at this time. I have reshaped the mould a bit, so we'll see if the next one does it.
Actually, the 6 has a little too much slope at the neck.
Mitch, shows ya what yer gettin' into...
BTW. if you are ever down in the Cities...

Your design is very similar to my MJ (OLF-MJ). Basically just a 16"LB vs. my 16 1/4"LB and a slightly smaller UB 11 3/8” vs. 12 1/16”. Your waist 9 1/4” vs. 3 3/8”

You will love this box. Expect big sound but not punchy like a dread.

Typo correction "Your waist 9 1/4" vs. 9 3/8" "