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I seem to remember Hanns Brentrup was able to edit a photo of a 19" Larson super jumbo to help him make plans for his own guitar. I was wondering how one would do this. I would really like to build a guitar just like this Torres, but there are no plans for this instrument. Does anyone know of any way to make reliable plans (I really just need the outline and head stock, the bracing isn't that complicated) with only the pictures that are available?

The Guitar

http://www.vintageguitar.com/3434/anton ... rres-1863/

I have been thinking I would like to build that too
The body length is given in the text so I would print the front picture, trace outline and soundhole and then enlarge on a photocopier until it matches the length

It would be very helpful if you had the usual dimensions of body length, upper and lower bout width, width at waist. With those measurements (and a photo) it's quite possible to produce an outline that will be close enough to the original. Practice and a trained eye helps.
i don't know if that photo is detailed enough to blow it up in software and then print it off.
Just remember that the original instrument is not going to be symmetrical. It's very likely that no half of the Top or Back is going to match. The usual course is to choose one half that appears to you to be the most graceful or alternately you can average out the differences.

You could always e-mail Richard Brune. There's a very good chance that he took real life measurements of that Torres.

This might help

http://myplace.frontier.com/~nostberg/plans/index.htm

It's a completely different guitar, but thanks anyway.

Read the text on the web page, lots of dimensions listed

Sounds like you could use the "Big Print" program from woodgears.ca. Here's the link:

http://woodgears.ca/bigprint/index.html

Pat

_________________
There are three kinds of people:

Those that make things happen,
those that watch things happen,
and those that wondered what happened.

Enlarging copier and 36" printer at Kinko's?

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Jim Kirby
kirby@udel.edu

If you have a cad program (I use turbocad) and max. dimensions (ie body length and lower bout), draw a rectangle in cad to those dimensions. Open the image you want to trace in "paint" or whatever, and crop exactly to the extremities of the body. Then import the image into the cad drawing and enlarge it so it just fits inside the rectangle. Outlines can now be traced full size & printed. (I draw little X's to help in overlapping sheets for full size patterns.)

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Dave
Milton, ON

I just pulled this into Solidworks and sketched on top of the photo scaled to a 16.75 body length per the text.
I have it as a C sized pdf if any one would like it let me know, or better yet pm me and I can send you the file. You should be able to get it printed at any print shop for a few dollars. I'll try to attach it here if I can. The file is a half pattern of the left half with the sound hole location and diameter.

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Jim Watts
http://jameswattsguitars.com

Deleted

Sorry, couldn't resist...

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http://www.presnallguitars.com

Wow, that's quite an interesting guitar there! I wouldn't have thought a 2mm top could handle a 25" scale without any fan bracing at all. Granted, the lute style no-saddle bridge means much less torque than usual. Looks like 0.8mm sides aren't such a good idea though

Let us know how it turns out. I may just have to make one as well

Thanks everyone,

I had both Charlie's and Jim's pdf files printed out at a local print shop and they look great. Thanks a lot, I can't wait to build this after I finish setting up my new shop.

Glad to hear it, Brian. I'm looking forward to see what you build

Looking forward to the build.

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Jim Watts
http://jameswattsguitars.com

Also with a photo the lens will distort depending on it's placement. Best to get a tracing. But then again you only really need to be close to the body shape. As we all know the magic isn't in just making an exact copy of the shape.

I've usually just brought the book with good photos to a copy shop and enlarged all the while checking the mm measurements.
To find the dimensions of things like pegheads and bridge width/length as well as rosette measurements (important to a properly proportioned copy), find a good photo of the detail that's not foreshortened and use the measurement data in the book and a rule or calipers.

use the following formula: X over Y equals X over Y

(unkown dimension "X") (measured unknown dimension "X" on photo)
over = over
(known dimension "Y" as per data) (measured known dimension "Y" from photo)

plug in your values, cross multiply and divide.

Work in millimeters.

Chris is correct. There is lens distortion which does complicate matters. Then again if you are within sensible limits I doubt that it will make much difference. Don't forget, the original instrument itself is probably not that accurate to the original template.

Just as a note, if you are so inclinded and have a good picture on the computer you can zoom in on the pic until you have it at 100% and trace it off the screen. Just like I did in making stencils for a National in this YouTube.
You can just skip the beginning and this technic is pretty much at the last two minutes.
If you have the known bout and length measurements you can also correct the lens angle distortion some with photoshop or some simular programs.