Official Luthiers Forum!

Just finished 2&3 doing 4,5,&6 now. I can't get my head around the geomentry of top radius and neck alignment. (No 2 had the dreaded 14th fret hump. What a pain.) I include the top of the heel block when I radius the top at 28r. But then I brace the top in the upper bought flat for the fret board extention. This sounds wrong to me. Can someone help me figure this out?

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Mark Ewing
Columbus Ohio
"Trees are an important and precious thing. We should build good things with them. Building good guitars with heart are the best use for them." K. Yairi.

Have you seen Hesh's "Flattening the Upper Bout" in the Fixture, Video, and Picture Tutorials?

René

You got a hump because your head block was radiused (sticking up on the inside edge) but your top's upper bout was flat. As Rene suggested, flatten the rims in the upper bout area before gluing on the top.

Or simply radius both ... works for me ...

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Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

There are two schools on this:

- use a flat UTB and flatten the upper bout of the rim
- use a radiused UTB that will go on the radiused rim, and flatten the area of the top where the FB will be glued afterwards.

I use a 3rd method for cylindrical plates, which is to use a radiused UTB, but flattened on 3" in the middle. The neck block (and upper foot) is also flat. That allows me to keep the top full thickness there.

The most important, with any method, is to carefully take into account your FB and bridge thicknesses (and how much the top may rise with string tension), and work the necessary angle at the neck block for a healthy saddle height and action, and no 12th or 14th fret hump.

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Laurent Brondel
West Paris, Maine - USA
http://www.laurentbrondel.com/

+1 for cylindrical tops. Mine's 15' and works perfectly...

What is the advantage of a cylindrical top over a dome? Do you have cylindrical dishes for gluing or just radius the braces?

Or is that a whole n'other thread...