Official Luthiers Forum!

As promised - Our next auction is for a 30' radius dish donated by Shane Neifer of High Mountain Tonewoods
This dish is made of two laminations of ? inch MDF and has been finished with two coats of Varathane Diamond Coat.
Thanks Shane!

This auction ends Friday Dec 16th at 12:00 noon est.
Going once, going twice, sold!
one dollar minimum bid amounts.

Thanks Shane

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Lance@LuthiersForum.com

$5

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Dave Bland

remember...

"If it doesn't play in tune...it's just pretty wood"

$20

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Tickle your guitar daily, and it'll tickle you back.

$25

I don't have any of these dishes yet. How does one figure out which radius to use?   

Thanks,Graham Steward38698.6203009259

25' for the top and 15 for the back are most common, although 30' for the top seems to be getting popular too. That is what I use.

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Lance@LuthiersForum.com

As Lance said, 25' foot for the top of a steel string guitar and 15 foot for the back are the most common. On classicals, I have been told and will use on my next project, a flamenco, 30 foot for the top and 25 for the back. Having said all of this, some, as with Lance, use 30 foot for the top on steel strings as they say it presents a natural neck angle. I am inexperienced in this regard. I make dises in 12, 15, 20, 25, 28 amd 30 foot radii. I can custom make any radius also, I am making a 10 foot dish for a mandolin experiment for one of my customers in the next week or two. These dishes are double ply as I feel that they lend to better balance and stability, rather than adding the extra layer after the dish is spun. It adds a bit to the shipping (these dishes weigh about 16 pounds) but I think that the quality is what we are after. So the lamintation is done before the dishing process.

Thanks and good luck!

Shane

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Canada

Hey Shane... one thing you might want to consider is making a matching convex cylindar segment to shape the bottom of the bridges with.

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Brock Poling
Columbus, Ohio
http://www.polingguitars.com

I bid $35.

Brock, after you win this baby and put some abrasive on it, a few strokes of a 2x4 on it and you'll have one.

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Tickle your guitar daily, and it'll tickle you back.

GREAT Advice John!! I like that a lot!

I am making matching radius templates for routing the curve on the bottopm of the brace, I tried to hold the brace on the rim sander and I just wasn't happy with it. Although one could do it by hand.

Shane

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Canada

[QUOTE=John How] Brock, after you win this baby and put some abrasive on it, a few strokes of a 2x4 on it and you'll have one.[/QUOTE]

I know there isn't much difference between a cylindrical cut and a spherical cut ... and I don't want to hijack this thread... but I would prefer a cylindrical cut.

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Brock Poling
Columbus, Ohio
http://www.polingguitars.com

Hey Brock,

I was at home and the way back to office I thought about your conical form. I could make them if there was a request. I would do it basically the same way that Craig makes radiused fret boards. The curve would just be a lot shallower.

What is the benefit of conical versus dished? Hi-jack away or we could move this to a new a topic.

Shane

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Canada

I don't know about anyone else's geometry, but my tops are not completely spherical. I flatten it above the sound hole and I sand my rims flat.

All of this is very slight mind you.

However, I find that profiling with a cylindrical arch is actually a little better for my bridges than a spherical arch.

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Brock Poling
Columbus, Ohio
http://www.polingguitars.com

Graham, I use 28' top radius and 20' back radius. I believe this is what is used at Martin.

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Don Atwood
Arlington, VA

$45.

So does anyone know why Steel strings use 25' & 15' radiuses and classicals use 30' & 25'?

I'm hoping that I can work out a way to use the same for both and save some money, but I don't want to save a bit of money at the expense of the quality of my guitars.



Thanks,

I used a 28' and 15' for mine.

Ron

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OLD MAN formerly (and formally) known as:

Ron Wisdom

Somewhere in the middle of Arkansas......

    I to use the 28-25 on dread and 28-20 on 000 and smaller. The stresses on a top are more.

Graham,

I am no expert on this but I will offer this. Cumpiano has stated a few times that the issue is not what the arc is it is just that there needs to be an arc. He still uses about a one inch strip of thin cork around the outside of his pattern on his work board to create his arc. Steel string guitars pull harder than nylon strings so it stands to reason that there is more force on the top. Having said that, 28 foot dishes are common for steel string and I would guess that the difference between a 28 foot arc and 30 foot arc over a 20 inch top is almost indecernable. The larger arch for the back I think is there to address the thinner wood typically used for backs (to keep weight down) and the need to ensure that they can withstand a bit more abuse. I personally don't see why you couldn't use 30 foot for tops (Lance does) and 25 foot for backs on steel strings. See how you like it and if you want more arch add another dish later on. Although you can use the same dish to sand and as a go-bar dish, by adding a layer a craft paper or news print over the sandpaper when using it as a go bar dish, I make two of each radius I use. I guess I CAN so I DO.

Hope this helps

Shane

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Canada

Graham, check out this thread from the archives. There are also a number of other threads that cover dish radius, so try the search function and good luck.

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Don Atwood
Arlington, VA

FYI!
This auction ends today at 12:00 noon est.
with a going onces, going twice, Sold!

Currently Brad has the high bid of 45.00

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Lance@LuthiersForum.com

GOING ONCE!!

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Lance@LuthiersForum.com