Acoustic Guitars

[mto93]

i am looking to build a classical guitar and was wondering what the appropriate length of the fretboard is for that type of guitar. 

[knockwood]

Are you referring to the scale length overall? Or the actual length of the fretboard itself? Not sure about the latter offhand, but typical classical scale length is 650mm. There are some made in short scale @ 640mm, and Kenny Hill has made guitars in 630mm length. 

A serviced guitar fingerboard from LMI will usually be about 20" or so in length, and you trim it to final length at your discretion, depending on where you prefer it to end relative to the sound hole. 

[mto93]

yeah i was referring to overall length of the board itself, tried to google it and all i got was the scale length which is handy just not yet.

[mto93]

also would a 5 inch sound hole be good enough or too big?

[DeepEnd]

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mto93 wrote:
also would a 5 inch sound hole be good enough or too big?

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'Way too big. Typical size is 84-90mm or about 3.3-3.5 inches depending on the volume of the body. Here are a couple of links that you might find useful:

http://www.classicalguitardelcamp.com/viewtopic.php?f=11&t=12151 (read all of this; there's a lot involved)

http://www.designofaclassicalguitar.com/dimensions.php

[knockwood]

If you're planning to build a classical guitar on your own, I would highly recommend reading William Cumpiano's Guitarmaking: Tradition and Technology. Not always the easiest read, but packed with an incredible amount of information.

I would also recommend Robert O'Brien's DVDs, available at LMI:

http://www.lmii.com/CartTwo/thirdproducts.asp?CategoryName=Videos%2C+DVD%92s%2C+CD%92s&NameProdHeade...

[Freeman_Keller]

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mto93 wrote:

i am looking to build a classical guitar and was wondering what the appropriate length of the fretboard is for that type of guitar. 

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I am assuming that you are building from some sort of plans - if so follow their measurements.   If not, the most common classical that most folks build as their first use the GAL plans for Segovia's 1937 Hauser.    That is 650mm scale length - the fretboard extension is approximately 117 mm to the center of the sound hole and about 125 mm to the edge.    Therefore the total length of the fretboard would be 450 mm - I wold buy it a little longer and shape it to fit the exact location of your sound hole.

If you want to do a shorter scale as Knock mentions you'll need to do the calcs.

I also looked up the measurements in Cumpiano - he gives the scale length as 25.6 inches and the distance to the center of the sound hole as 17-27/32.   See chapter 3.

[Freeman_Keller]

[Freeman_Keller]

Brain fart.   In my earlier post I put the wrong length (I fixed it).   For 650 mm scale, the 12th fret would be at 325.    Add about 125 for the fretboard extension to the sound hole is 450 mm (which is pretty darn close to the 17-3/4 inch from Cumpiano).   Probably the best way if you are designing your own is to use this fretboard calculator, your desired scale length, the number of frets.   Note that it will also calculate nominal compensation for the bridge locations (classicals are compensated but not angled - ie the same amount for both ends of the saddle).

[Freeman_Keller]

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mto93 wrote:
also would a 5 inch sound hole be good enough or too big?

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 Sound hole size has a big effect on tone - just ask Tony Rice.    The Hauser plans call for 86mm (about 3-3/8)

[mto93]

now how important is the placement of the sound hole, i've seen pictures of guitars with them all over the guitar but they are always forward(toward the fret board) on the guitar. i know i want to centered but not such how far up from the end it should be.

[knockwood]

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mto93 wrote:

now how important is the placement of the sound hole, i've seen pictures of guitars with them all over the guitar but they are always forward(toward the fret board) on the guitar. i know i want to centered but not such how far up from the end it should be.

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If you want a more or less "standard" sound hole placement, I would strongly suggest working from plans and/or with a template. Both are available from a variety of sources, but I tend to buy most of this kind of stuff from LMI. They have numerous plans for different classical body styles.

If you'd prefer to do something more *experimental* with the placement of your sound hole, you can place it pretty much anywhere you want it, so long as you work out the bracing to go along with your desired placement. Not difficult at all, I would imagine, but kind of a coin toss in terms of final tonal result. I'm not very familiar with classicals in general, but some steel string makers are known for unusual sound hole placement. McPherson and Tacoma come to mind immediately. Tim McKnight, a very accomplished luthier who sometimes visits this forum, uses sound *ports* on his upper-bout bass sides. I'd suggest trying to find some guitars with uniquely-placed sound holes and try them out yourself to see what impression the different placement makes on you.

[knockwood]

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Freeman_Keller wrote:

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Man, that is really gorgeous. I love Hauser-style bodies and would really love to try making a classical some day. What are the specs on this one, FK?

[Freeman_Keller]

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mto93 wrote:

now how important is the placement of the sound hole, i've seen pictures of guitars with them all over the guitar but they are always forward(toward the fret board) on the guitar. i know i want to centered but not such how far up from the end it should be.

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The length of the fretboard, size of the sound hole or its location really don't matter one little bit.   Build your guitar, post some pictures and clips and we'll discuss more.

[Freeman_Keller]

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knockwood wrote:

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Man, that is really gorgeous. I love Hauser-style bodies and would really love to try making a classical some day. What are the specs on this one, FK?

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LMI partially serviced kit, 37 Hauser plans.   Sitka over EIR, nitro - nothing really special.   Interesting learning experience - Spanish heel, building on a soleria, planing relief into the fretboard - lots of differences from a steel string.   Here is a very old thread - might help the OP understand what he is getting into.

http://www.kitguitarsforum.com/archives/threads.php?id=186_0_6_0_C

 edit to add - obviously I haven't figured out how to put pictures where I want them LOL

[mto93]

ok here is what i am thinking for the general outline of the body. designed this myself so if you think it wont work this is my first design. so is there anything specific i need to change?

[mto93]

i also have another question. how important is it to curve the back? it shouldnt be too hard to do but it would be easier to just have a straight back.

[Freeman_Keller]

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mto93 wrote:

ok here is what i am thinking for the general outline of the body. designed this myself so if you think it wont work this is my first design. so is there anything specific i need to change?

mto93 wrote:

i also have another question. how important is it to curve the back? it shouldnt be too hard to do but it would be easier to just have a straight back.

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Mto, please pardon my saying this but either you are very naive (which is what I thought originally) or a troll.   Now I'm not totally sure what to think.   Remember that there are several very nice folks here that are trying to help you.

Your body shape will probably work but its going to be a bitch to bend those sides.   Generally we like nice curves that combine a series of arcs - there are pretty good reasons that traditional guitars look the way they do.  Air volume affects something called Helmholtz resonance - without calculating your volume there is know way to know how it will sound.   Even if you are able to bend that shape, you'll never find a case to fit it (I pay about $300 to have custom cases made to fit some of the odd guitars that I build).

Next, again, the back (and top) are dome shaped for several very good reasons, including structural.   A dome is much stronger than a flat piece of wood and will move as humidity changes.   A flat back and top will crack.  There is some theory about the way sound wave bounce off a spherical back - I wouldn't worry about that if I was you.    Also, most guitars are deeper in the lower bout than the upper - you can't do that without some curvature.

I don't know anything about your wood working skills or for that matter, what you are seeking with this guitar.   For most of us the challenge of building a tradtional design that sounds half way decent is hard enough - take my humble advice, buy plans (or a kit) for your first one - you can get creative in the future.

[mto93]

ok first off i cant say i am not a troll i have just never done this before, which is why i am here. now as for all the technical crap you were trying to throw at me i have taken physics which is why i do understand how sound reacts to different shapes and in different volumes however unless you have come up with some magical way of calculating the volume of the guitar without actually having it complete is impossible, granted you can get a rough estimate using two larger cylinder calculations. on the other note i do appriciate all the help i have recieved from everyone here i just dont like to be insulted. and as for my design i did think that my curves needed to be moved down/up slightly to allow for more gradual curves and allow for easier bending. and i do have plans which i am following for general guidance on bracing placement and general shape but i enjoy challenging myself because i do concider myself handy and wanted to do something that i thought looked a little better granted my shape does look kind of funny, but all that aside do the general measurements of the body sound good so i can draw up a new shape with less extreme of curves. thanks again for all the help and sorry if i seemed rude im just not too thrilled being called a troll i would more or less go with inexperienced.

[Freeman_Keller]

OK, I'm going to ask a bunch of questions and while they may seem insulting, it will help me better understand what you are trying to do.   Give me good straight answers and I will help you in any way I can.

1 - Why do you want to build a guitar?

2- Why do you want to build a classical guitar?

3- What is a classical guitar?

4- What classical guitars have you played?   What did you like/not like about each?

5- What other guitars have you played/owned?

6 - What kind of music will you play on this guitar?  What style or technique?

7- What materials will you use to build this guitar?   What is your budget?

8- Describe your shop.   What power tools do you have?   Hand tools?   Lutherie tools?  What is your budget for additional tools?

9- What have you read about guitar construction?   Books?  DVD's?  Build threads?   Did you read the thread that I linked?   What have you learned from these?

10- What do you plan to use for the following design criteria

• Scale length
• nut and saddle width, fretboard radius
• neck joint, peg head style
• bracing pattern

11- How do you plan to do the following operations

• thickness the plates
• bend the sides
• carve the neck
• shape the bridge
• miter the fretboard
• cut the sound hole

12- Will you build on a workboard (soleria), mold or ?

13- Will your guitar have a rosette?  Binding?  Inlay?   How will you do each?

14- Do you understand guitar geometry?   Fret location, action height, relief, intonation, compensation?    Have you done a "set up"?

15- What kind of finish will you use?

Please understand that I am not trying to insult you but questions about fretboard length, sound hole size and location, and body shape indicate that you might not have studied the fundimentals very carefully.   And while there is some very interesting work being done with classical guitar construction, most of it is based on some very traditional designs.

btw - if I don't respond to this for a couple of days its because I will be away from computers.