All Koa Baritone Uke - which for top and which for back?

[sburke]

I just started working on an all koa baritone ukulele. IMHO the wood looks fantastic. I began by thinking the top pic would be the "top"
Now I am now wondering which piece should be the top and which the bottom. Thoughts?

 

[merlin666]

Do a tap test and pick the one that gives you a better vibration for the top.

 

[sburke]

Do a tap test and pick the one that gives you a better vibration for the top.

Good idea. Thanks

 

[BradDonaldson]

Tapping may give some indication of stiffness, but I would weigh and flex them, looking for the lightest and stiffest of the two for the top. From the picture, I would lean towards the top one as it has the straightest grain.

 

[sequoia]

I would definitely go with the top pictured wood. The figure reminds me of vibrations coming out of the instrument.

 

[Ziret]

Gorgeous wood. On looks alone, I’d go with the pro answers, the top one is way prettier.

 

[Pegasus Guitars]

With the 2nd 1, you are basically gluing endgrain. The center seam will move and show some unevenness before too long with any change in humidity, no matter what you do. Best to use it on the back. I personally don't use wood that has that much of a chevron pattern. Just too much endgrain. Good luck with your project.-Bob

 

[Pete Howlett]

Wise words Bob and Brad. As you and I know, working with figured woods involves more than a passing relationship with basic woodworking techniques and timber technology. BTW, the definitive research based ideas work for ukulele makers is the now not often quoted Left Brain Luthierie by David Hurd. I couldn't understand much of this erudite treaties but his 'flexion' testing rig and ideas are really useful for those who use a scientific approach.

 

[sburke]

Thanks for the input and the education. I chose the top one for the reasons above, especially.
Straighter Grain and nice flex. Currently at 2.2mm
Good Tap Tone (kind of bassy but will brighten when braced)
Looks

Will post more as the build progresses.

 

[Pete Howlett]

Thanks for the input and the education. I chose the top one for the reasons above, especially.
Straighter Grain and nice flex. Currently at 2.2mm
Good Tap Tone (kind of bassy but will brighten when braced)
Looks

Will post more as the build progresses.

View attachment 138230

TapTone is a red herring.... try getting a consistent stiffness to mass ratio.

 

[sburke]

TapTone is a red herring.... try getting a consistent stiffness to mass ratio.

Actually, I tend to agree yet you see people refer to it all the time. To me, there are too many variables in such a test although I can hear differences between boards, etc
I read a little of the Somogyi information but would like to know how to calculate a stiffness to mass ratio and what would be considered a "good" ratio?
Thanks

 

[sequoia]

Thanks for the input and the education. I chose the top one for the reasons above, especially.
Straighter Grain and nice flex. Currently at 2.2mm
Good Tap Tone (kind of bassy but will brighten when braced)
Looks

Will post more as the build progresses.

View attachment 138230

That is going to make a beautiful looking ukulele. I also like the thin, understated ab rosette. It works well with the figure of the wood. I'm guessing the sides are going to be Koa also?

 

[sburke]

That is going to make a beautiful looking ukulele. I also like the thin, understated ab rosette. It works well with the figure of the wood. I'm guessing the sides are going to be Koa also?

Yes, sides are also KOA.

 

[Pete Howlett]

David shares his ideas in his book.

 

[counsel1]

That is going to make a beautiful looking ukulele. I also like the thin, understated ab rosette. It works well with the figure of the wood. I'm guessing the sides are going to be Koa also?

 

[Sporky]

Fantastic result

 

[aaronkb]

That’s gorgeous can we hear it?

 

[a green field]

Well done!

 

[frets alot]

Gorgeous!

 

[Michael Smith]

Nice Work