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[quote=Howard Klepper]BTW, if anyone doesn't know how to make a "long compass," here is a very helpful page from Jon Sevy. This is a nifty and simple jig for drawing large radii. [/quote]

Long Compass
Pretty Dang Cool! I assume one just sets the centerline of the pencil to the chord height from the centerline of the pins. You could do any radius you like! Never seen it before! Thanks Howard!

Look like there's a jig to be made!

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Billy Dean Thomas
Covina, CA

"Multi famam, conscientiam, pauci verentur."
(Many fear their reputation, few their conscience)

The dome is one constant radius or sphereical segment, but because the shape of the body is not one common width or the same distance from the center of the dome everywhere, the intersection of the body with the dome has an ever changing elevation. The closer to the center of the dome the taller the side profile. The further from the center of the dome the shorter the side profile.

Our Traditional series features the same 25' radius prepared into the braces, but the sides are left flat for a more traditional build style. This build style tends to have a more traditional tonal character, emphasizing a bit more bass.

What do they mean by "left flat"? Cut to a straight taper before bending and then not trimmed? Trimmed so that the top edge of the sides is in one plane? Something else? I'm having trouble seeing how this doesn't describe a pretty weird construction method, that would put some odd kinks into the top.

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

[QUOTE=Howard Klepper] Our Traditional series features the same 25' radius prepared into the braces, but the sides are left flat for a more traditional build style. This build style tends to have a more traditional tonal character, emphasizing a bit more bass.

What do they mean by "left flat"? Cut to a straight taper before bending and then not trimmed? Trimmed so that the top edge of the sides is in one plane? Something else? I'm having trouble seeing how this doesn't describe a pretty weird construction method, that would put some odd kinks into the top.[/QUOTE]

I could be very wrong but the way that read to me is that they cut the kerfed lining flat to the top instead of having a little angle on it to reflect the radius of the top.

That would in turn make the edges of the top stiffer, which, from what I've read in the archive and am yet to experience, would give the guitar a bassier sound.

Coule be completely wrong though given I'm a build virgin...

Howard it is no surprise that I agree.

I believe most that do not sand the dome into their sides/linings/ blocks leave the top side of the rim flat, install the linings flush to the top edge of the rim, then forcibly clamp the dome shaped top so that the perimeter of the top meets the linings causing the dome to be deformed at the perimeter. Now we are only talking about deforming the dome shape 1/16" or so. How ever that 1/16" is adding stress that the shape is trying to resist, and that stress never goes away. The worst place is at the waist.

As others have said, several major builders build this way. I my self do not wish to add the added stress on the top by deforming the shape of the dome I induced by radial bracing. So I sand the dome into rim, linings, blocks and all so that when I lay my top down to glue up. the top contacts the linings and blocks without having to pull them down.

If I did not want to sand the dome into the linings I would at least sand the rim till the sides intersected the dome everywhere then add my linings. Then you would have only about 1/64" that needed to drawn down during glue up.

Hesh I built two that way as well back several years ago. Neither have failed. I did not notice ant difference in bass response. But did not notice is lack of response either.

I doubt there are may that have had failure issues doing the flat pull. but to me it is kind of like using a set of sides you have under bent and forcing them to fit the mold. It is just unneeded stress IMHOP.

     I think the stress from using flat rims would be short lived, eventualy the wood would  relax and assume the shape it was formed ( or deformed) into  . Jody

Micheal - Do you sand the sides in the shape mold (with heel and neck blocks but no linings) with the radius dish and then glue in linings slightly proud of the newly sanded edges of the sides and then sand the linings down to the edges of the sides? 

Thanks,

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Steve Walden
Aspiring Builder,
Bartlesville, OK

I never can remember if it is 'ae' or 'ea'....

Thanks, Michael!

 

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Steve Walden
Aspiring Builder,
Bartlesville, OK

Yes! I sand the sides, while in the mold to real close to the dome. Install the linings the finish the sanding. This makes my rim fit the dome pretty close to perfect. When I lay my top dopwn on my sanded rim the linings sides and blocks meet the top everywhere (baring some minor movment of the braced top.

Ok, so not satisfied with the pigeon/cat ratio of my initial innocent-sounding question, I have another.

So, we have our radiussed top, which for argument's sake we'll say is attached to radius sanded kerfed lining and sides.

So let's now introduce a cutaway.

Is it generally acepted to radius the cutaway in relation to the overall radius of the top, or are the edges of the cutaway radiussed inwards to suggest a secondary mini-radius only affecting the area of the cutaway?

Uh, ok even I don't understand what I wrote.

Think of it this way - take your sides/ head and tail blocks in their mold with the linings proud. Rub the whole lot in a radius dish covered in sandpaper. Now all the radiussed edges are 'correct' as per a perfect dome covering the top of the guitar. However, the bit inside the curve of the cutaway will at one point be radiussed so that the lining would have to angle the opposite way to normal.

I hope I'm making sense here...

I am missing your point Dave .. the cutaway area has the same radii as the rest of the top - it is highest at the deepest part of the cutaway (closest to the top of the dome), and falls away from there - I am about to bind three of them (florentines), and I make the binding piece for the cutaway extra tall, then plane in a rise in the bottom edge before installing as the piece is small/tight enough that is doesnt want to bend to accomodate the curvature of the binding ledge - you will almost always get a gap at the deepest part of the cutaway as the binding tends to want to lean forward, away from being tight in the ledge.

Maybe in order to see your issue, go back to Michaels cookie cutter analogy in a sphere - just add a cutaway to the cutter - nothing really changes as far as the dome is concerned - its kind of like a deeper waist area thats all.

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

in your minds eye imagine a dowel sticking through both poles of a sphere. kind of like the rotational points on a globe

This is the center axis of the dome. Now take the cookie cutter with the shape of a cutaway guitar body and slice down with this pole sticking parallel to sides of the cookie cutter and centered in the middle of the area inside the cookie cutter. the only difference in the cutaway make is how close to the center axis any point of the cutaway is. The closer to the pole a parallel edge the tall that parallel edge is.

That is the only change that happens. There is never a radial change in a spherical segment.

::edit:: Oops, looks like courier new isn't a monospace font after all

Uh, if it's impossible to recreate the above with imagination, I'll do some drawing and scan em...

PS the above post was started before you wrote your explanation MichaelP, it just took me a while to type it all up...

I am creating a 3d model with a Sphere and cookie cutter it will be a bit but I will post when done

[QUOTE=MichaelP] I am creating a 3d model with a Sphere and cookie cutter it will be a bit but I will post when done[/QUOTE]

Michael,

Do we all get a slice when you've done it? Yum, Yum

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Dave White
De Faoite Stringed Instruments
". . . the one thing a machine just can't do is give you character and personalities and sometimes that comes with flaws, but it always comes with humanity" Monty Don talking about hand weaving, "Mastercrafts", Weaving, BBC March 2010

I have a strong preference for Chocolate Chip, please! 

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Waddy

Photobucket Build Album Library

Sound Clips of most of my guitars

Ok! here are the pics
The first two are a side view and isometric view showing a guitar shape and a transparent sanding dish. I decrease the bowl radius a bunch to make what happens easily visible
]

Next is an isometric view of the rim sanded. I made the rim thich to eliminate drawing all components. Followed by side and neck end views The red is the surface left by sanding.


Notice the waist is the tallest part of the profile because it is the closest area to the center axis of the dome. The neck and heel occupy the equal elevations but all other point are subject to their position of intersection with the dome or sphere. Now this is exaggerated. by the small radius I used.

How many of you are suprised tat you body gets taller in the middle?

[QUOTE=MichaelP] How many of you are suprised tat you body gets taller in the middle? [/QUOTE]

How many of you are surprised that your body gets taller in the middle?

It is not that I can not spell it is that my keyboard seems to not record my every key stroke... That's my story and I am sicking to it

Michael,
Do you flatten the area under the fretboard extension or leave the SR?

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"An adventure is only an inconvenience rightly considered. An inconvenience is an adventure wrongly considered." G. K. Chesterton.

[QUOTE=MichaelP] [QUOTE=MichaelP] How many of you are suprised tat you body gets taller in the middle? [/QUOTE]

How many of you are surprised that your body gets taller in the middle? [/QUOTE]

TALLER?!?!? I'm surprised! Since I turned 40, my body has been getting WIDER in the middle!!

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now known around here as Pat Foster
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http://www.patfosterguitars.com