Radius for top and back of rims clarification...

[Legolas]

Okay, so i'm getting ready to rough radius my rims. The
dishes i ordered will be in next week. I have
watched John Hall's videos and i hope John will chime in
here.

Anyway, so i do the back first (no blocks or kerfing yet) with a 15'
radius. I draw chalk on the sides and "drive the bus" as
John says. Once the chalk lines are gone then I'm done.
Correct?

Okay, then on to the front. First I true up the sides using
the flat side of the dish. Then I use the 28' radius to create
my slope. Now this is where I get a bit confused....Do I want
a radius (slope) on the whole front rim except the area of the neck
and tail blocks? Or do i want the slope in the neck and tail
block area?

I don't wanna screw this up on my first build because I know
how critical it is for proper neck angle.

[johnnparchem]

I would follow John's videos your description sounds correct. I put a 28 degree radius on the whole top side, the 28ft radius will closely match the neck angle you want. When I brace the top and radius the braces I flatten out the curve of the transverse brace under the fret board.

[tippie53]

I do it pretty much as you guys spoke but with 1 clarification , once the top is on and you are done pre setting the neck I use a flat stick with sandpaper on one end. I want the area we create the angle on to be flat and true with the neck.
The stick rides the neck and the sand paper end helps true this extension area to the neck plane for a dead flat transition area.

[Legolas]

I would follow John's videos your description sounds correct. I put a 28 degree radius on the whole top side, the 28ft radius will closely match the neck angle you want. When I brace the top and radius the braces I flatten out the curve of the transverse brace under the fret board.

So, you just leave the 28' radius on the whole top rim edge
(including the blocks) and that sets you up for the correct neck
angle? You don't flatten any section?

[Ben-Had]

Not to confuse anyone but to throw a different process in the mix and show there are different way to skin a cat or in this case radius a guitar.

I sand the top dead flat, then sand my neck angle onto the top (also dead flat but at the proper complimentary angel to my neck) from about the top of the sound hole to the neck block. The radius for the top is sanded into the x braces. All the top braces are glued down on a flat board and the x braces spring back once they are glued down.

Key is not to mix processes.

[johnnparchem]

I would follow John's videos your description sounds correct. I put a 28 degree radius on the whole top side, the 28ft radius will closely match the neck angle you want. When I brace the top and radius the braces I flatten out the curve of the transverse brace under the fret board.

So, you just leave the 28' radius on the whole top rim edge
(including the blocks) and that sets you up for the correct neck
angle? You don't flatten any section?

I do flatten the part of the brace under the fret board. Other than that everything you say is correct about my process.

Tim describes another way that works.

[Legolas]

I would follow John's videos your description sounds correct. I put a 28 degree radius on the whole top side, the 28ft radius will closely match the neck angle you want. When I brace the top and radius the braces I flatten out the curve of the transverse brace under the fret board.

So, you just leave the 28' radius on the whole top rim edge
(including the blocks) and that sets you up for the correct neck
angle? You don't flatten any section?

I do flatten the part of the brace under the fret board. Other than that everything you say is correct about my process.

Tim describes another way that works.

So, just to be clear, you flatten the neck block and the rim that
it's glued too? Or are you just keeping the transverse brace flat?

[Kevin Waldron]

Tim B,

Not following what you do.... can you explain a little more...... sorry........

If I understand.... you are forming a radius on the top with the braces shaped to some radius but you sand the rims/kerfing/lining flat?

Blessings,

Kevin

[Ben-Had]

Tim B,

Not following what you do.... can you explain a little more...... sorry........

If I understand.... you are forming a radius on the top with the braces shaped to some radius but you sand the rims/kerfing/lining flat?

Blessings,

Kevin

That's correct. It is the exact same process the Martin factory uses (only their machines are fancier). You can hear Chris Thomas discuss it here (listen close from 35 to 45 sec into the video):

http://www.youtube.com/watch?v=rAu3Nw4KYdo

After their machine sands it perfectly flat it hydraulically tilts it 1.3* to sand the rim flat from the neck block to just about the top of the sound hole at that 1.3* angle. The arching comes from the bracing only on the top. The back has a slight radius to it, I do mine at 12' radius.

[Legolas]

Tim B,

Not following what you do.... can you explain a little more...... sorry........

If I understand.... you are forming a radius on the top with the braces shaped to some radius but you sand the rims/kerfing/lining flat?

Blessings,

Kevin

That's correct. It is the exact same process the Martin factory uses (only their machines are fancier). You can hear Chris Thomas discuss it here (listen close from 35 to 45 sec into the video):

http://www.youtube.com/watch?v=rAu3Nw4KYdo

After their machine sands it perfectly flat it hydraulically tilts it 1.3* to sand the rim flat from the neck block to just about the top of the sound hole at that 1.3* angle. The arching comes from the bracing only on the top. The back has a slight radius to it, I do mine at 12' radius.

I saw the video. Now I'm wondering why I'm doing a radius on the
top rim at all. I'm trying to get this dread as close to Martin specs
as i can.

So, maybe I'll just radius the braces for the top. Do i radius the
transverse brace as well?