Other Guitars

It starts with a slab of mahogany…

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1.5" slab glued up from from furniture scraps

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Then the robot turns most of it into sawdust

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Lots and lots of sawdust

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Looks like the start of a beautiful relationship.

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Once the robot has finished feasting on mahogany,, we have something that vaguely looks like a guitar

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Stay tuned for tomorrow's adventures with sand and glue

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A CNC gets the job done in less time than it takes you to THINK about it if you are doing it the old fashioned way. A customer of mine who builds stand-up basses for classical bass players got a 3 axis CNC machine a couple of years back. The robot cut his carving time to a fraction of what it had been when he did it all by hand. Less time roughing out the top and back plates means more time to tap tune and refine the top where it really counts.

You're fortunate to have access to some advanced machinery. Keep posting the process as you go. Are you using African or American mahogany?

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To be fair, I spent hours on the computer refining my design. Measuring parts, editing curves, moving screw holes...But yeah, it's stupid easy to use this thing once the drawing is done. I've had printers that were more difficult.

Regarding the mahogany, I have no idea. I just pull scraps from the pile that look thick enough to use. It's quite a bit lighter in color than most mahogany I've seen on guitars--more of a gold than an auburn.

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Your set-up time is time well spent. Even if you were going to hack out a guitar body with a band saw and hand-held router, you would have spent lots of time tweaking the design. The computer remembers what you've told it to make, and can do it over and over again without much fuss.

What will you use for the top?

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I'm going to try a variety of tops. Right now, I've got prepared pieces of ash, birch ply, and masonite. You can see the ash lying under the guitar in that last photo.

I see the final product as a combination of Danelectro, Bigsby, and Fender Thinline. With my own tweaks of course

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It's looking really cool.

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Very nice! I can't wait to see the rest!

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I think it needs a little more work before you can gig with it.

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looks very promising Otter, cool!

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That is cool! It looks kind of like a Thinline Dano.

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That actually looks like Asian mahogany to me.

Also known as Meranti.

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Out of curiosity (and a desire to procrastinate at work), I've done some research on mahogany types.

It seems there can be quite a bit of confusion (and perhaps marketing trickery) when it comes to identifying types of mahogany. The American types (Cuban and Honduran) are known as "genuine" mahogany, while African and Asian types are often called mahogany due to similarity in appearance (but not necessarily mechanical properties).

The local lumber mill's (the supplier for my boss's woodshop) website indicates they produce "genuine" mahogany, Swietenia macrophylla. They do not appear to sell any other types of mahogany, leading me to believe this is the American variety. They get a lot of their wood from Belize.

A guy who works at the lumber mill occasionally hangs out at the woodshop. I will ask him next time I see him.

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If you are a hard-core purist, the one true mahogany is Cuban mahogany (Swietenia mahagoni)...a wood native to Florida and the Caribbean. This is the wood that all that expensive antique American furniture was once made of....and the Spanish Armada.

Cuban mahogany is pretty rare and expensive these days. The trade embargo with Cuba never helped the situation. It has been planted a bit here in south Florida and even some Asian islands...but even during the heyday of American guitar manufacture in the 20th century...it was already being substituted for HONDURAN mahogany (Swietenia macrophylla) by Gibson, Martin and other manufacturers.

So which mahogany is "real mahogany"? If you are a traditionalist to luthier history you's have to go with Honduran...because that's what a 1959 Les Paul is made of. If you are a traditionalist to American historical woodworking...you'd have to say Cuban.

Now there ARE woods using the term "mahogany" that aren't even the same GENUS as Swietenia. To further confuse matters, species of Swietenia cross-fertilise readily when they grow in proximity. The hybrid between S. mahagoni and S. macrophylla is widely planted for its timber.

Personally I recognize the genus Swietenia to be "mahogany" and consider Asian and African mahoganies to be "substitute mahogany"

That's not to say that substitute "mahoganies" aren't viable and maybe even superior woods to make musical instruments out of. "Real" mahogany has the problem of being "on average" bit too hard and dense to make guitars out of...and guitar manufacturers are often tasked at finding the lighter examples to make guitars out of. In terms of appearance, a guitar made out of true Cuban mahogany might be kind of heavy, dark, and look like you were playing a stick of antique furniture. And since it's rarer...it might have pin knots, sapwood, be slab cut instead of quartersawn and have other defects as a sacrifice to being "real mahogany"

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Yamaha use a timber they call nato where mahogany might be used otherwise. It's quite non-descript - looks a bit like meranti but appears to be a bit lighter.

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A CNC gets the job done in less time than it takes you to THINK about it if you are doing it the old fashioned way. A customer of mine who builds stand-up basses for classical bass players got a 3 axis CNC machine a couple of years back. The robot cut his carving time to a fraction of what it had been when he did it all by hand. Less time roughing out the top and back plates means more time to tap tune and refine the top where it really counts.

You're fortunate to have access to some advanced machinery. Keep posting the process as you go. Are you using African or American mahogany?

– Viper

All of which makes you wonder why there aren't more carved top guitars being made in this CNC era. Even if the builders aren't going to go to the trouble of tap tuning, you'd think there would be more examples of carved tops being marketed as superior to pressed tops with an upcharge to match. I guess interest in solid spruce tops in the hollowbody/archtop world is already fairly limited. Maybe it just isn't worth any extra effort to go carved rather than pressed.

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I saw the machine used for carving tops at the Santa Cruz Guitar Co. about 20 years ago. It was big and I bet very expensive. I wouldn't be surprised that it took a long time to pay off. IIRC their archtops go for +/- $8K.

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Afire, carving tops via CNC only saves you one step in a long and skill-intensive process. I suspect a lot of the people who have the rest of the skills to complete that process learned to carve tops the hard way and are pretty satisfied with their workflow. As easy as the CNC is, I quite enjoy working wood by hand as well.

Also, carving wood that thin, that quickly, can lead to warping as the relatively moist wood in the middle is exposed to the relatively dry air so suddenly. Carving the wood slower allows each new exposed face of wood to equilibrate to the atmospheric conditions.

Of course this is just speculation, as I have none of the skills involved in building archtop guitars.

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The main advantage of CNC is being able to mass produce identical units. I found it easier to fix a error on a CAD drawing than with the standard old school drafting I learned originally. CNC offers the same benefit. Good luck!


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