Official Luthiers Forum!

My day gig is sort of a cross between an electrical and mechanical engineer. I think in terms of details on just about everything I do regardless of work or home related. But at the same time, I love to get into a project and design as I go. I work one step out and them come up with the solution for the next. Every once in a while this bites me in the ass.

So I am considering a new guitar design. I have the body drawn out full scale and it looks great. At one point I had made the guitar mold, but between my house and my dads, we can no longer seem to locate it. So I will be building the mold again. BTW: Its a small body archtop electric guitar with a florentine cutaway. At this point in the process should I already be thinking of bracing designs? My gut says, build the sides and top/back and then consider the bracing once I can see what I have to work with. I know the bracing is a little less tricky on an archtop, than a flat top, but I was wondering what you guys do.

How about you? Do you fully design your work first, or play as you go?

Thanks,
Joe

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Joe

Well.. If you have the body and sides drawn to scale you basically already know what you're into. Since you're going to have to design the braces anyway.. Why not start sketching out some designs?!? You might choose to tweak them once you get to gluing them to the top (for top tuning purposes)... But with a full scale drawing you have the ability to see where you might run into trouble before you start cutting wood. Also you have the option to try several different designs without it costing you more than some ink and paper

My 2 cents...
Cheers!
Chad

I make a full size drawing ;even of the bridge.
I use #2 pencil so if i need to change anything it's easy to erase my lines.
Plus they look good hanging on my shop wall!

That way i can walk up to them and revaluate things if I have to.

Mike

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Mike Collins

I do a full scale drawing of the body, bracing, soundhole, rosette etc. I would definitely do the bracing and make sure everything works out before getting started.

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David White, Toronto

"All my favourite singers can't sing."

I'd definitely draw out the soundhole position, saddle/bridge position, and braces before I started
to cut wood. You'll need to define the scale length to finalize all of the above. I can't see any
downside to drawing out all of this, and seeing things like where is the bridge going to go in relation
to the lower bout, where is the X-brace intersection with upper and lower bout edges, etc, is very
important to the design...

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Gene

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

This is an interesting question. I personally find that I do better designing first and then building. If find this process to product better results with less errors and rework.

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Brad
Avon, OH

I was taught and for a good reason (it proved out) got to have a plan, whether on paper or in your head and then go with that. If not and start improvising as you go and shooting from the hip, will probably miss the target. That sucks, I know, that is why the boss drilled the plan and sticking with it into my head.

Edit...

I find this process to produce better results.....

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Brad
Avon, OH

Only done this once so far, but it's way easier in the long run (no nasty surprises) if you draw it up full size before you start cutting wood.

Definitely work out the major architecture of the instrument first.

Some things become very evident when you can see it full size, and in relation to other elements. Somethings you can leave till later.

If it's something that I haven't built yet, I often make a plywood cut out of the guitar, just so I can get a better sense of it, .

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Expectation is the source of all misery; comparison the thief of joy.
http://redrivercanoe.ca/

Thanks everyone. I guess in this case, I have the guitar drawn out, but I don't have any concept of what style bracing I will use. I also don't have a good feel for the height of the arch in the top yet. I was thinking a shallow arch but when I get to that point, I may find it really needs something a little taller. Until I really understand how all the pieces affect each other, trial an error is part of the process. I am doing a lot of research, but when creating your own design and concept, its hard to capture exactly how others designs will affect my own.

I did order the Benedetto book to see if that guides me thru part of the design stage as I go. Its said to have good discussions on the bracing etc. So that will help, but I have a feeling a good portion is still going to be trial and error.

JD

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Joe

From an acoustic guitar and design engineer’s point of view. I go about designing new models this way.

First I draw the basic concept out in cad complete. Keeping in mind that it is a prototype I do not over detail but do draw components in place and detail enough to fabricate. Working all things out on paper or cad in my case avoids unforeseen fit up problems that may be over looked.

Then I build the first prototype per the plans. Making notes of desired or need changes and revising the drawing accordingly. I build prototypes till I am happy with the model always making revisions to the drawings as a record of those changes. Each revision is a cad file drawing unto it's self so that i can go back ato a specific revision level at any time. Of course prototypes are not the end. As I build each production version of a model I learn more and more about that model and when necessary I make changes to my cad drawings to reflect changes made during building.

From a manufacturing engineer's point of view the design drawings comes first, but continually evolve with the product.

In the manufacturing world it is extremely rare to find a set of fabrication drawings that have only one iteration or revision level. Design and manufacturing of a single product or mulitiple products is never a static science, but rather a disciplined kinetic process.