Guitar Outlines

[B. Howard]

Wonderful link John, Thanks!

[rienk]

I've finally gotten around to doing some CAD work, and have finalized my guitar shapes.
I basically did an analysis of the Martin shapes, along with some of my other favorites, and came up with a formula for how I wanted all my sizes to progress - all the way from a Jumbo down to a parlor (including sizes that correlate to a dread, OM, 00, 0, etc). Attached are some print outs of what they will look like. This is a progression of 8 different shapes - though we intend to only do a couple to start with. They are Model number 28, 30, 32, 34, 36, 38, 40 and 42 (which stands for the width of the lower bout, in centimeters). The body length ranges from 45-52cm respectively, and all the other dimensions are a progression as well (13 different parameters for the main body shape, plus five more for the cutaway).
I have attached three different comparison files.

The first shows the model shapes in direct relationship to each other. On the right are the actual sizes overlaid on each other. On the left are the same models, but scaled to show how they would compare if they were all the same body length.

The second file shows all eight models spread out (and the larger models show how they will likely look with a cutaway).

The third file shows some direct comparisons to other guitar shapes.All the green outlines are my shapes. The comparison on the top left is my 12-30 compared to a Martin Parlor; the second one is my 14-34 compared to a typical classical; the top right is our 14-36 compared to an OM. The bottom left is our 14-38 compared to a McPherson, the middle is our 14-40 compared to a Martin Dread, and the bottom right is our 14-42 compared to a Jumbo.

Uke outlines still to come, but for now, we are building our new side bender designs (waiting on materials from McMaster) and the molds for the 14-38 and 14-40.

[johnnparchem]

Fun work. I like how most of the shapes worked especially the smaller shapes. Did you come up with your shape differences algorithmically? I like the dread sized guitar with the tighter waist as well. I always thought a dread looked like they cut a guitar in half and added extra wood to the middle.

[rienk]

Fun work. I like how most of the shapes worked especially the smaller shapes. Did you come up with your shape differences algorithmically? I like the dread sized guitar with the tighter waist as well. I always thought a dread looked like they cut a guitar in half and added extra wood to the middle.

Thanks to another member, I discovered the guitar design software called 'G-Thang.' It's not perfect - but it's free!
Using that saved me SO much cad time... and though I like the design process, I do actually want to get around to making guitars.
Using the parameters already set up in the software, I worked through various iterations of what I wanted to end up seeing. I happen to love using spreadsheets, so I have some fairly detailed/complicated sheets of all the different guitar sizes and shapes I could find, and then did some mathematical comparisons - including all sorts of ratios (I used at least 10 ratios in my matrix) as well as perimeter, top area, and guitar volume comparisons. Even had to use some calculus to get to the bottom of it.
But the reality is that so many guitars are very similar in size and area, etc. I happen to like some of the concepts that McPherson uses, but I didn't want to go quite as extreme as some of his shapes (he uses a fairly small waist and upper bout). In the end, I was able to figure out where the various guitars differentiated on the list of parameters, compared the ratios I tracked, and came up with a related "series" of shapes that smoothly transistioned through the different sizes, and came very close to the handful of guitars that were the inspiration for the series.

I think they look great - and they show a level of design consistency that I have not yet seen in other builds.
I hope to start molds and bending forms next week!

[rienk]

Next I will be developing the bracing patterns that I will be using; with our cnc capability, we will be doing somewhat of an interlocking truss style bracing pattern. McPherson's is innovative and pretty, but more style than substance (IMHO). I will be using Baltic Birch plywood for all of our test bracing (in fact, most of our test guitars will be made completely out of Birch ply). If it weren't for the fact that guitar buyers (and builders?) can be snobbish when they lay out so much money for a custom guitar, I would use the ply for all the bracing - even in the 'real' guitars... has anyone tried this, or at least considered it?