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 Post subject: Mahogany guitar tops
PostPosted: Fri Feb 16, 2024 8:09 pm 
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Koa
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So I luckily have a few large Honduran mahogany rift sawn boards. Contemplating making an all mahogany 000. I realize there are plenty of things to consider but in general, would you make the top somewhat thinner than say a sitka top? Say ten to twenty thou thinner?



These users thanked the author Darrel Friesen for the post (total 2): Kbore (Fri Feb 23, 2024 7:40 am) • bcombs510 (Fri Feb 16, 2024 8:38 pm)
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 Post subject: Re: Mahogany guitar tops
PostPosted: Fri Feb 16, 2024 8:12 pm 
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Brazilian Rosewood
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I made my first Mahogany topped OM a few years ago. I used the same deflection numbers I used for spruce and it turned out quite well. I’ll have to look up what the thickness came out to be.

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These users thanked the author Terence Kennedy for the post (total 3): Kbore (Fri Feb 23, 2024 7:40 am) • Pmaj7 (Tue Feb 20, 2024 3:39 am) • bcombs510 (Fri Feb 16, 2024 8:38 pm)
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 Post subject: Re: Mahogany guitar tops
PostPosted: Fri Feb 16, 2024 9:23 pm 
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Koa
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I’ve done one. Based on advice from here, I thicknessed it to equal the deflection (by feel) that I normally use for spruce tops. It came out at .117” a bit thicker than I usually use for spruce. It sounded wonderful.



These users thanked the author bobgramann for the post: Pmaj7 (Tue Feb 20, 2024 3:40 am)
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 Post subject: Re: Mahogany guitar tops
PostPosted: Fri Feb 16, 2024 9:45 pm 
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Koa
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Thanks guys. I had some of the same thoughts around stiffness and likely weight too.


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 Post subject: Re: Mahogany guitar tops
PostPosted: Mon Feb 19, 2024 4:00 am 
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Brazilian Rosewood
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Generally if you are sanding to deflection mahogany will wind up thicker than spruce.

The last few that I’ve done I’ve made them 20% more flexible and made up the stiffness with the bracing and they’ve been pretty successful guitars…



These users thanked the author meddlingfool for the post (total 2): Kbore (Fri Feb 23, 2024 7:40 am) • Pmaj7 (Tue Feb 20, 2024 3:41 am)
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 Post subject: Re: Mahogany guitar tops
PostPosted: Mon Feb 19, 2024 9:31 am 
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Brazilian Rosewood
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The mahogany I've tested has had Young's modulus numbers along the grain that are pretty close to the denser spruces. A strong 'stripe' figure is a sign of lot of run out, and that reduces long-grain Young's modulus values. Since that's the primary thing that determines how thick the top needs to be, you end up making them about the same thickness or a bit more depending on the figure. However, mahogany is usually denser, so the top weighs more. This is going to favor bass over treble, and 'headroom' over 'responsiveness', and less power overall. Naturally, each piece is different.

I've often thought that a cedro ('Spanish cedar') top would be a natural choice with mahogany B&S. The look can be similar, but cedro tends to be lower in density, with decent long grain stiffness. It may be hard to find in sufficient width, though. I remember seeing three cedro planks at a yard about 25 years ago that were 2" thick, 10 feet long and 40 inches wide, but they were flat cut. Impressive.



These users thanked the author Alan Carruth for the post (total 4): Kbore (Fri Feb 23, 2024 7:39 am) • Pmaj7 (Tue Feb 20, 2024 4:07 am) • Darrel Friesen (Mon Feb 19, 2024 9:38 pm) • Bryan Bear (Mon Feb 19, 2024 3:07 pm)
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 Post subject: Re: Mahogany guitar tops
PostPosted: Mon Feb 19, 2024 10:00 am 
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Alan Carruth wrote:
I've often thought that a cedro ('Spanish cedar') top would be a natural choice with mahogany B&S.

Yeah, I would like to try a cedro top. Another I've always wanted to pair with mahogany B&S is primavera. Similar look but lighter colored. Lower Young's modulus than cedro so it would be heavier, but still lighter than a mahogany top of equal stiffness.


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 Post subject: Re: Mahogany guitar tops
PostPosted: Mon Feb 19, 2024 12:19 pm 
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Brazilian Rosewood
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Primavera makes a fine non spruce sounding top…



These users thanked the author meddlingfool for the post (total 2): Pmaj7 (Tue Feb 20, 2024 4:07 am) • Bryan Bear (Mon Feb 19, 2024 3:07 pm)
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 Post subject: Re: Mahogany guitar tops
PostPosted: Mon Feb 19, 2024 9:40 pm 
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Koa
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Alan Carruth wrote:
The mahogany I've tested has had Young's modulus numbers along the grain that are pretty close to the denser spruces. A strong 'stripe' figure is a sign of lot of run out, and that reduces long-grain Young's modulus values. Since that's the primary thing that determines how thick the top needs to be, you end up making them about the same thickness or a bit more depending on the figure. However, mahogany is usually denser, so the top weighs more. This is going to favor bass over treble, and 'headroom' over 'responsiveness', and less power overall. Naturally, each piece is different.

I've often thought that a cedro ('Spanish cedar') top would be a natural choice with mahogany B&S. The look can be similar, but cedro tends to be lower in density, with decent long grain stiffness. It may be hard to find in sufficient width, though. I remember seeing three cedro planks at a yard about 25 years ago that were 2" thick, 10 feet long and 40 inches wide, but they were flat cut. Impressive.

I have a few planks of Cedro that I usually make linings with. I can taste it as we speak. Good call on trying it for soundboards. My try it and build it list will definitely outlast me I'm afraid but it is on the list!



These users thanked the author Darrel Friesen for the post: Kbore (Fri Feb 23, 2024 7:39 am)
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 Post subject: Re: Mahogany guitar tops
PostPosted: Mon Feb 19, 2024 11:37 pm 
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Brazilian Rosewood
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I can taste it too and I haven’t had a taste for years, lol…



These users thanked the author meddlingfool for the post: Kbore (Fri Feb 23, 2024 7:40 am)
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 Post subject: Re: Mahogany guitar tops
PostPosted: Tue Feb 20, 2024 9:44 am 
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Brazilian Rosewood
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Cedro has to be one of the best smelling and worst tasting woods out there.



These users thanked the author Alan Carruth for the post: Kbore (Fri Feb 23, 2024 7:40 am)
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