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Hi! Compliments for the forum, it seems a great place to learn and share!
I'm just a newbie, my experience on guitar making is limited to an about 60 hours class I've attended in Rome in which I could build a SS guitar followed full time by a luthier. Here's some pic of the guitar (Martin 000 with cutaway, italian spruce top, mahogany back, side and neck, rosewood fingerboard, ebony bridge):

http://img252.imageshack.us/img252/3937/pb070065.jpg
http://img5.imageshack.us/img5/4082/pb070066.jpg
http://img260.imageshack.us/img260/7214/pb070067.jpg

Now I'm preparing to do my second guitar, I've already bought a Martin OM plan. Actually I'm making a cad model from it (having a little CNC I can cut my mold, templates and so on...), when I'll have it done I'll be able to easily scale it down.

I'm not very tall and I'd like to build a guitar a little smaller than normal, but not so much to even get to a 7/8.

Let's say that a 9/10 scale would be more than enough. (Actually I was thinking to a 9.2/10 ratio to use a 14 1/4" truss rod instead of a normal 15 1/2")

Would it be correct to scale down just ALL of the quotes of the original plan? Just anything, from frets scale to fretboard thickness, from strings distance and gauge (like 0.10 instead of 0.11) to saddle compensation, from top thickness to braces sizes, and so on.
Is it the right concept when scaling down a guitar? Or do some parameter have to be constant or even increase when the others are scaling down?

Thanks
Best regards
Marco Pastorio

I can't see the edit button, I'd like to add some thoughts...
(reading back I also noted that I wrote 0.10 & 0.11 gauge instead of .010 & .011 ... I'm used to think in mm, not using the .0 notation...)

Just by thinking about it, using lower gauge strings on a shorter scale may not be a good idea: a shorter string will need less tension to reach the same pitch, and so does a lower gauge string. Adding these factors may lead to loose strings. Moreover, a smaller guitar will tend to sound brighter, so relatively heavier strings may help the lows...
Mounting a relatively heavier strings may imply that some element should not be scaled down. I refer to neck thickness and braces. Anyway, given the shorter scale and the lowered tension, it may be ok to scale down braces anyway (for the neck there shouldn't be problems as in my case it will be laminated, so on its own stiffer than the original mahogany neck).
Should I keep the braces stiffer than in the original project? Maybe not scaling them in height only?

Are there other parts that are not to be scaled?

Thanks
Marco

Without getting into "correct" or not, I'll say that it's unusual to just scale down every part of a guitar. If you look closely, Martin didn't even simply scale a OOO body to get to their OO body. (Although I prefer the look of a pure body scaling.) But, certain things like the height of the strings above the soundboard, fingerboard thickness, even the peghead, you may or may not want to leave alone.

I'll also mention that when Martin switched their guitars to 14 fret models they kept their high end (rosewood) OOs at 12 frets. Also, when Martin has done some special edition Rosewood OOs they often make the body deeper.

Besides scaling a Martin, you may also want to look at other guitars. For example, a 14 Fret Gibson L-OO.

John

Scaling down is not the best way to get a smaller guitar. As Todd pointed out, there are plenty of smaller guitars that are already designed and known to work well and it's always a good idea to start there.

There are relationships that don't necessarily scale. For instance, most smaller guitars tend to get narrower more than they get shorter. This is due to the fact that the scale length and body length can only be shortened so much before you start to really compromise the sound (or at least change it from what people have come to expect from a guitar).

Also, neck width and thickness are typically independent of other factors.

Good luck.

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http://www.chassonguitars.com

Hi!
Thanks for the informations!

I found a couple of 00 free plans, this ones:
http://grellier.fr/plans/Gibson_L-00/Gibson_L-00_fr.pdf
http://grellier.fr/plans/Acoustic_guita ... _00_fr.pdf

One is of a gibson L-00 and the other seems more similar to the free plan of the OM guitar from the same site, but scaled down. The OM I refer to is this one:
http://grellier.fr/plans/OM_acoustic_gu ... tar_fr.pdf

The Gibson has in fact different proportions between body and neck, with the body just 1mm shorter than a OM but with the frets' scale 20 mm shorter.
The 00 instead is more similar to a scaled down OM: body/fretboard scale proportion is the same between 00 and OM, with 00 scaled down of about 0.97:1.

Anyway the braces of 00 seem to be scaled down only in length and relative position inside the body; thickness and height are instead more or less the same.

Body width of 00 is less than 0.97:1 scale confronted with OM, but Gibson is even narrower in width. Considering the almost unaltered body length the reduced width is much more pronounced.

Gibson's braces are thinner but with a different shape, I don't know how to compare them to 00's and OM's.

Both Gibson's and 00's bodies are indeed deeper than OM's.

I don't know how accurate these free plans are, but they indeed follow the guidelines you guys just indicated.

Would it be opportune in your opinion to scale down by myself my Martin plan following these plans guidelines on what has to be scaled, what has to kept and what has to be enlarged?

Probably I'll keep the scale somewhere between 24.5" and 25", without going down under 23.5 as I originally thought.

What do you think about it?

Thanks
Best regards
Marco Pastorio

yes, everything is possible , is just that some things are more possible than others.

blessings
cuh
Padma

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Audiences and dispensations on Thursdays ~ by appointment only.


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I thought scale length was a constant . That is, you can scale the body, but not the neck, unless of course you pick a different scale length.

Ok

A guitar, or just about any stringed instrument may be scaled, or any portion of it may be scaled any which a way your heart desires. Big or small box, long or short neck. Long tall skinny ones, big fat short ones. ~ NO matter.

Or as Yoda taught us.."size don't matter"

What is most important is knowing how to brace for the bridge placement of the desired string length.

However it is advisable to have built a few of the various assorted sizes so as to get the gist of the concept as to what it all entails as the "bugs" have already been worked out before one just jumps in and starts messing around.

My suggestion is... decide on what size and shape you are after and then design the instrument starting from the nut, to the bridge, add the shape and then figure out the bracing.

blessings

Padma

_________________
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Audiences and dispensations on Thursdays ~ by appointment only.


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I have built four of the Grellier L-00's now. This guitar is now my personal favorite shape, its a perfect size for sitting on the couch and just playing for fun! The upper bout is small enough to be comfortable and the lower bout is large enough to still sound good.
Highly recommended!
Mikey

_________________
The Biggest Little City, Nevada
www.hammondguitars.com
I love building guitars!

Thanks!

I think I'll go with a 00, still don't know if martin or gibson style. Honestly, esthetically I like a bit more the martin's shape, the gibson looks a bit "skinny" on the upper bout.
Still undecided about the sound (which is the most important part...). Listening from some youtube videos I'd say that gibson seems more aggressive and wooshy (let's say jazzy) while martin seems more clean and balanced...

@mhammond: did you make any soundclip of the L-00 you built? I searched the forums but I couldn't find any...


PS: OMG, I totally missed Todd's post! Must have been blinded...
Thanks, I'm listening to some 0's samples too!

As Padma says... All things are Possible... Some things are more possible than others...

When scaling down -- you scale down the outside dimensions of the body...
Typically, you have to re-design the bracing scheme
You have to pick a scale length that you prefer, and design an appropriate neck
You also have to choose a comfortable neck width and bridge saddle string spacing
You would also pick a "Standard" string weight that you are comfortable playing. Frequently, super-duper ultra light strings don't give volume and tone like "Standard" string weights to.... Especially so on a shorter scale length....

The typical method is to first pick your scale length, string spacing at the Nut and Saddle...
Then pick the neck to body joint location fret # -- This determines the location of the bridge...
Then, adjust your outline to put the Bridge where you want it on the body
Then, design a bracing scheme to overlap the bridge however much you want....
Add the sound hole whatever size you need for the body size

Then... Build it.

Or... Pick a "Standard" plan that already uses the scale length and body dimensions you want... and follow it.

Thanks

John

Ok, thanks again for the input!

At least now I know that there are rules to follow to scale down a plan, it's not just reducing everything proportionally!

Probably the martin-style 00 is the best way to go for the 2nd build.

I noticed that Grellier's free plans have scalloped braces on both 00 and OM, while the OM plan I bought form lmii doesn't have scalloped braces.
If I understood correctly, scalloped braces should help a little to bring out lower notes, am I right? I suppose this may help on smaller guitars...

I also noticed that martin-style 00 from lmii is made by Grellier as well!
Would buying lmii's plan give more detailed informations and/or better proportions? Or can I stick with free plans? In fact I would have to scan lmii's plans (as I did with OM's plan too) to bring them to vectors to make my molds and templates, so being the free version available in dwg/dxf would help a bit...

Anyway a close confrontation between grellier's and lmii's OM plans show that there are several differences even in critical places, as in braces' placement relative to bridge and braces type itself.
What would you suggest to follow?

Thanks
Marco

Hi, I'm still doing some confrontations between the various plans.
I've put to vectors the top layout (including bracing, bridge, etc...) of the LMII's Martin OM, scaling it down to match Grellier's 00 I've noticed that outline's proportions (height to width ratio), even sound hole placement and size are almost matching. Adding the 633 mm scale neck I've also notice that it fits quite well the bridge placement of the scaled down OM.
The only major difference is the X braces' placement: on the 00 they are closer to the sound hole, of more distant from bridge placement if you prefer, of a noticeable amount.

I was wondering, what's the reason for this? Does a bridge placed on a less supported area helps somehow to balance the smaller proportions?