Official Luthiers Forum!

I've built quite a few guitars. This is my first ukulele build. I'm building a tenor uke with a 17" scale and a 12 fret neck. The body is Clark walnut.I am curious about a couple of details. 1. Do you typically radius your tops? I'm using lutz spruce, and a very stiff piece I might add. 2. If not, do you use a neck angle or do you keep it 0 degrees with a flat top? How thin can you take a top down to? I have mine down to 2 mm, but toward the tail it got a little too thin(1.4 mm in some spots.) will that be strong enough? Any suggestions, advice would be appreciated.

Thanks,

Coach

_________________
change isn't synonymous with improvement
instagram.com/bucketguitars/

Coach:
I normally thickness to 70 thou (0.070") for mahogany and 75-80 thou for cedar.
I have been using an eight-foot radius dish but never get the full curvature for some reason.
I often use Spanish-heel. I clamp the neck on the bench and slide the soundboard into place.
I use many of the techniques and dimensions from the Hana Lima book.

Bob

1. No. But there are more than a few who do. One of my friends does a "cylindrical" radius, only on the lower bout. Very shallow, 25' or less (or more, depending which way you look at it).

2. Either way, 0 degrees. I have another friend that throws in a 1/2 degree on his factory tenors. However, he does a 15 fret join, if that makes any difference.

Sorry Coach, you can do the math conversion, but I take my Sitka tops down to about .070" depending on the top. They'll naturally thin (by design, within my process) on the edges when sanding the binding.

Per the internet, most guitar builders will overbuild their first ukulele. You don't seem to be like most. The concern I'd have for you with 1.4mm is you have a 12 fret join, which puts the bridge closer to the tail, all things being equal. If I thinned a piece to less than .060", I'd probably throw it away and start over.

Of course, i do a 14 fret join, not that it makes a difference.

My thickness on uke tops varies from.070 yellow cedar -to .110 for spalted sycamore.Thickness is realized by density, stiffer tops are thinned, and softer tops are thicker with added stiffer bracing

2mm is about right for a spruce top. 1.4 sounds a bit thin but you might be ok if its over the tail block/kerfing/bridge plate, etc.
I do about a 1 to 1.5 degree neck angle on tenors because I like low action and I use pre-made bridges. I also use a 16' radius on the top. I'm not sure why really...just scared of truly flat tops I guess