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Ukejungle
11-21-2014, 02:07 PM
I played a Collings Concert Mahogany Uke the other night- amazed how light it was. Anyone have any idea how thick their tops are? Must be part of it. It sure did sing.

Trey

sequoia
11-21-2014, 06:06 PM
I built a mahogany tenor and the top was 0.067 which I thought was pretty thin. A concert could even be thinner. My thin mahogany did not sing however. Not bad and no log, but no Collings I'm sure... I've actually been looking at top thicknesses on friends commercial ukes and have been known to even put calipers on them. Conclusion: Top thicknesses are all over the place from a potato chip 050 to an Oscar Schmidt fir top that was 110 (actually sounded pretty good).

I'm just an amateur builder "enthusiast", but I think, all other critical issues aside (necks, nuts, bridge height, neck set, etc. etc. etc.), it is the soundboard and a thickness that is appropriate for the type of wood that really makes an uke "sing" and therein the secret lies. This is not news obviously, but nuances and subtlety are mind boggling. Funny, I think I know a good tap tone (maybe), I just don't know how to make it happen with the wood... But I'm tryin! I might just get lucky, cause otherwise, it is trial and a lot of error.

Sven
11-21-2014, 09:04 PM
As with all woods, "mahogany" covers a great range. Different sub species, different trees and different pieces. I've got mahogany on one shelf in the shop, and you'll find anything there when it comes to stiffness. So a number for the thickness of a particular uke might not transfer well to another.

Sven

Pete Howlett
11-21-2014, 09:46 PM
So anyone going to answer the question?

Timbuck
11-21-2014, 11:05 PM
So anyone going to answer the question?

Best ask Mr Collings ;) contact here http://www.collingsguitars.com/contact.html

DennisK
11-21-2014, 11:51 PM
I built a mahogany tenor and the top was 0.067 which I thought was pretty thin. A concert could even be thinner. My thin mahogany did not sing however. Not bad and no log, but no Collings I'm sure... I've actually been looking at top thicknesses on friends commercial ukes and have been known to even put calipers on them. Conclusion: Top thicknesses are all over the place from a potato chip 050 to an Oscar Schmidt fir top that was 110 (actually sounded pretty good).

I'm just an amateur builder "enthusiast", but I think, all other critical issues aside (necks, nuts, bridge height, neck set, etc. etc. etc.), it is the soundboard and a thickness that is appropriate for the type of wood that really makes an uke "sing" and therein the secret lies. This is not news obviously, but nuances and subtlety are mind boggling. Funny, I think I know a good tap tone (maybe), I just don't know how to make it happen with the wood... But I'm tryin! I might just get lucky, cause otherwise, it is trial and a lot of error.
Don't forget that the top thickness doesn't have to be the same all over either. Concert and soprano ukuleles are small enough that soundboard mass is basically a non-issue, so it's possible to build without fan braces at all. Just the two cross braces above and below the soundhole for structure.

One way to approach it is to have the goal be that every point of the soundboard is under equal deflection. If the thickness is equal all over, then it deflects most right around the bridge, and least at the perimeter. So you vary the thickness to counteract that. Or you can add braces, and vary their heights to get a similar effect, which is what most people do. Or some combination of the two.

Bracing gives more control, since thickness affects stiffness in all directions at once, whereas braces can be angled any way you like. So in the braceless style, you can only control long grain versus cross grain stiffness by selection of soundboard wood.