Modifying guitar plans

[Jules93]

I’ve already got plans for a j45 (slopped shoulder dreadnought)

I’d love to make a 12 string version in time but these days plans are soo expensive even PDF plans that you can print to scale still come at a cost obviously not including the cost to print them.

Anywho what’s the best way adapt the plans I mean there’s lots to consider and changes from
Neck widths, brace patterns, brace height ect

I’ve got the steel string construction book by Irving Sloane which gives you plans (not too scale) with measurements for a dreadnought12 string would that be enough?

[TallDad71]

The words ‘false economy’ spring to mind.

If there truly is lots to consider then there of a greater chance of structural incompatibility, an over or under build. Building a guitar is a long, emotional journey, perhaps it’s better to start it on a solid foundation of tired and tested measurements?

[Taffy Evans]

Hi Jules 93, First, let me say that I think the cost of a plan is not that great compared to the other components and materials needed to build a decent guitar. Possibly less than the cost of a fingerboard. If one does not have enough experience to make the required adjustments, then a plan for the instrument in question may be the way to go.

I have had the luxury of doing repairs for over 50 years, and have always, from day one, noted the build details of every type of guitar from a whole range of manufacturers. From this, I learned what caused a guitar to fail, why older guitars did not fail, and importantly why they sound the way they do. I also built my first 12-string from the book you mentioned in 1980, it worked for me.

I have found that one or two books on luthiery do not give the full story, and I have also had plans that have given me a bum steer at times.
I just had a quick count and must have 60-plus plans for different instruments, purchased and created over many years.

The bottom line is a plan is like buying insurance but be prepared to modify it. Information on some dimensions may not suit the tonewood characteristics, for example.
Taff

[kiwigeo]

I don't work without a plan....and being a bit anal I go to the extreme of drawing up a full scale layout of string runs so I get it right with things like bridge pin holes etc.