Official Luthiers Forum!

I will be going to the LMI "garage sale" coming up soon. I went to the last one out of curiosity and came home with some unbelievable deals on many different items. Now that I am on my first build and much more knowledgeable on what to look for, I plan on buying some tops and sides for future builds. What is the absolute smallest length and width you would consider usable for a dreadnaught or 000 sized guitar?

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Brad Hall
Mystic Dawg Guitars

Personally? I like to buy top and back halves that are at least 1/2" larger than my pattern on both sides. So, if I am building a guitar that will be 16" wide, I make sure that my top and back wood is at least 8.5" wide for each half when I buy it. This gives me room for creating a good center seam without worrying about whether I am running out of wood on the outside edge.

A minimum of 1/2" extra on the width for me too. At least an inch extra on length but I prefer longer to allow room for lengthwise positioning of the pattern to best fit any figuring or to avoid any imperfections.

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

I've cheated on length before but width is tricky. You can use wood that's the same length as the body....the binding will hide the edges. Width depends how confident you are on making the center joint. If you can get it right the first try then you can use wood that's just as wide as the body and hide the edge with binding

You sure you don't have that backward? It is possible to scarf things together length-wise, but it's tricky, and the seam will always be visible.

I really don't care much about width of backs unless I have a specific design in mind. A center wedge just looks like an extra fancy backstrip. You can add wings on soundboards too, which can be pretty much invisible, but I prefer not to.

I prefer to have 1/16" overhang all around on the top/back. Any more is a waste. But even 1/16" under all around is fine since the binding/purfling will cover it.

Factor in your jointing skill and the roughness/curvature of the joining edge when measuring width. Backs need to be a touch longer than tops due to the depth taper creating a longer path. But otherwise, there's not much need for anything beyond the guitar design dimensions.

Even if you end up too narrow on a top there are a few cheats. I'm working on a top right now that was pushing it for width. I hade more trouble than normal with the center seam and am now just a bit shy in the lower bout. I was't worried because I knew this guitar was going to get wide purfling And binding. I still may end up a tiny bit shy. If so, I'll fill you in n with some wood from the waist. No one will ever be able to see it. You can actually get a fair amount of lower bout width from the waist area if you are't opposed to glueing on "wings".

Short answer, it is nice to have an extra 1/2 inch to allow for jointing but don't pass up on a good deal for a nice top of it is a little shy of that.

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Bryan Bear PMoMC

Take care of your feet, and your feet will take care of you.

You cheat on length on the sides by making large end grafts. If necessary, even on the end where the neck is attached.

Also, the sides don't have to meet at the neck end, because the neck heel covers it.
On backs and tops, the 'cheating' on width or length is accomplished because of the binding and purfling. The standard Martin 28 style purfling is 1/8" or a bit more, and the binding is 1/16". That means you have about 3/8" in length or width as a fudge factor. Pearl top Martins have even wider purfling.
Similarly, sides can gain some width if the kerfing is set proud. The gap can be covered by the binding.
Also, the back can be widened if the decorative center strip is glued between the halves, rather than set into a routed groove. Martin has always joined their backs this way.
As far as allowance for joining tops, that gets better with experience. Nowadays, my main issue there is to cut off any oxidized (darkened) edges, because I prefer using older wood. If you don't, the top could end up with a darker stripe at the seam.

To answer the question:

Dreadnought
Tops and backs = 7 3/4 X 20
Sides = 4 5/8 X 30 3/8

000 14 fret
Tops and backs = 7 7/16 X 19 3/8
Sides = 3 7/8 X 29 1/4

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John

John, did you mean 29 1/4 for OOO sides?

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Bryan Bear PMoMC

Take care of your feet, and your feet will take care of you.

Ha, I learned that one the hard way

Theoretically, you could gain up to 1/2 pr more this way, depending on the width of your binding. Although 1/4 to 3/8 would be more practical.

AND don't forget to leave an equal amount of heal/tail block the same amount. Damhikt

AND don't forget the heal block on the back side will need to be even taller towards the center of the back due to radius. Damhikt

AND even if you have the clever idea to graft on to the bottom of the heel block to account for the radius, that you will be able to see it through the sound hole. Damhikt (.....Celtic sound hole cover?)

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Pat

Another point not mentioned is that you can make your Dread or Triple O a little shorter or a little narrower and still have a nice guitar. I build many different instruments, so I make the instrument fit the wood.