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Would someone please be so kind as to explain the top radius? How it is done?

Mike

All of the braces are made with a radius in them (there are a couple of ways of doing this) and the sides will have a radius in them as well. Then the top is essentially bent over these radiused members. This usually happens in a dished form so all of the radii match up in a uniform manner.

Another cosideration, the higher the number radius like 40' gives deeper tone(more bass) and a smaller radius like 15' increases the pitch(more highs). So average builders use 25' for the top and 15' for the back. Hope that helps a little more.

So to glue on the top, one way is to use a go-bar deck and a radiused dish in the bottom of the deck that corresponds to the radius you put on your braces. The braces are pressed down on the top, which is pressed down into the dish. Good luck!
Tracy

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Tracy
http://www.luthiersuppliers.com

Mike,

It looks like you are a fairly new luthier (as am I). I'd suggest you look at Kathy Matsushita's "Amateur Luthier" website "http://pweb.jps.net/~kmatsu/". It's a very comprehensive pictoral description (several guitars worth)of how guitar's are built, and what tools are used- like the go-bar deck Tracy mentioned.

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Gene

Politicians and diapers must be changed often, and for the same reason- Mark Twain

Yes, I am new to this...and am reading and learning. In the process of getting a 000 from John Hall. He mentioned the mold was radiused.

Mike

I'll 2nd Kathy Matsushita's web page. It not only gave me a lot of tooling ideas but also gave me a lot of insperation.

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Say what you do, Do what you say.

Mike, here's a pic of a 25' radius dish in the go bar deck, the guitar top is in there with the braces that have been sanded in the same dish with a big round sheet of 80 grits sandpaper and their bottoms now at the same radius of the dish are being glued on the underside of the top with flexed bars , hope this helps! Serge

   HI
   The mold isn't radiused the side set is.
http://www.bluescreekguitars.com/tutorial12.php
   This link will show you what that means. The side set when bent and trimmed will have a radius placed on them. The radius may influence the tone though I never hear the difference . What it will do is give the top and back strength and allow for the wood to move during humidity changes.
     The side set will have the contour placed and on the top and there is another benifit . The neck angle is about 1 1/2 degrees. The top has a 28 foot radius and this allows the fretboard to make a smooth transition to the top and helps to eliminate the 14th fret hump.
    THe radius is set to the side so the matching brace radii fall on smoothly. IF you don't do this the edges are forced and the joint can be compremised. You need the joints to be smooth and not forced. A force joint will fail.
    Hope this explains what some of us do to mate the plates to the rim
john hall

A few days ago I wrote a fairly long post involving different methods of
radiusing tops and some effects on tone. It was long so I don't want to
post it twice, but it's n the "Baking Tops" discussion (probably on page 2 or
3 by now).

The radius, or crown of the top is certainly important for structure, but can
be of equal or greater importance for tone. I've never been a big fan of true
flat top guitars myself, though I know some people love them.David Collins39096.3023263889

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