Dreadnought plans questions

Morecowbell
Posts: 280
Joined: Thu Feb 21, 2019 10:51 am
Location: Fishers, IN

Dreadnought plans questions

Post by Morecowbell »

About to start a Dreadnought for my son and have a few questions on plans:

1) Are there any sources that are better/more accurate than others? StewMac, LMII, GAL,

2) If I want to do a cutaway should I used the LMII plans or eyeball the StewMac plans (non-cutaway)

3) What do people recommend for top and back radius?

4) Which version do people recommend for the bracing pattern?

Many thanks!

Clay
"Facts seldom sway an opinion." - John Hall
"The difference between theory and practice is that in theory there is no difference." - Van de Snepscheut
MaineGeezer
Posts: 1711
Joined: Wed Aug 13, 2014 12:14 pm

Re: Dreadnought plans questions

Post by MaineGeezer »

Here's an anarchist's opinions :-) It is totally uninformed about actual facts, so beware.

I wouldn't worry about the "best" plan. What you need is the general body shape and depth.

Having done one cutaway, I'd never do another one except under extreme duress.

My usual radii are 25' top, 15' back, but a dreadnought top is so big I might try 28'. Not sure about the back.

I've had really good luck with my own version of falcate bracing (see "The 00 Project" in "Blog Your Project" and "Show it off.") The sound coming from that 00-size body is incredible. I totally winged the bracing, and it could have been a disaster. You may want something that is more certain of a good result. (For that matter, the 00 may still be a disaster if the bracing fails in a year or two.) I hope somebody else will have the nerve to try it though.
Don't believe everything you know.
Anything is possible if you don't know what you are talking about.
When things are bad, try not to make them any worse, because it is quite likely they are bad enough already. - French Foreign Legion
Morecowbell
Posts: 280
Joined: Thu Feb 21, 2019 10:51 am
Location: Fishers, IN

Re: Dreadnought plans questions

Post by Morecowbell »

Haha, thanks for the thoughts and disclaimer! :-)

Now that I've made it through one the plans actually don't concern me as much as they did, but I enjoy looking at them and building in my head, part of my process borne of lots of nights looking at model airplane plans I'm afraid.

I'm still on the fence re the cutaway but my son plays up there which is why I'm considering it, and of course its a new challenge.

I did some quick research on Dred radii and was surprised to find that it doesn't seem set in stone - didn't expect to have to ask about that one!

I'm looking forward to checking out your OO build thread, I'm dipping my toe into the Trevor Gore water with "Left Brain Lutherie", am interested to see where that goes, and of course would like to understand what I can. I did lots of tapping and listening and even did some recording without any clue of what I was doing so interested to shed some light on that if possible.
"Facts seldom sway an opinion." - John Hall
"The difference between theory and practice is that in theory there is no difference." - Van de Snepscheut
Kevin Sjostrand
Posts: 3712
Joined: Sat Feb 09, 2008 8:06 pm
Location: Visalia, CA

Re: Dreadnought plans questions

Post by Kevin Sjostrand »

I've been using a plan drawn by Scott Antes, back in the 90's I believe and sold by LMI I think.
Like it was said, body shape for making your mold is needed. Bracing patterns are usually Martin style and tiu can play around with A LITTLE the thickness and height, scallops, etc.

Mine have always been 30' top and 15' back radiuses.
A 88.5" neck angle usually comes out about right.

I too did one cutaway back when I was bending on an iron by hand. The bending wasn't so bad just getting the neck block-fretboard all correct was a bit stressful.

I made a press for cutaway for my fox style bender and after two trys bending a cutaway on it I gave up.
That was back when I was using only light bulbs for heat in my bender. Since I got a blanket and controller years ago I should try the cutaway again. I bet it would work.

Good luck with your next one, a Dred. Fun fun fun.

Kevin
tippie53
Posts: 7011
Joined: Fri Mar 03, 2006 7:09 pm
Location: Hegins, Pa
Contact:

Re: Dreadnought plans questions

Post by tippie53 »

antes plans I find were terrible and over braced
Gen one is also useless
the MacRostie plans are good
CadGuitar plans

MacRostie and cad guitar plans are based of true martin guitars
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
Morecowbell
Posts: 280
Joined: Thu Feb 21, 2019 10:51 am
Location: Fishers, IN

Re: Dreadnought plans questions

Post by Morecowbell »

Kevin - thanks for the thoughts. After my last post I did a little research on acoustic cutaways and read a very funny take that basically said, "that's for electric guitars". i.e., acoustics just don't have much power or sound that high on the fretboard so why bother? I'll talk to my son, I think he has an acoustic cutaway so will see what he thinks.

John - thanks on the plans, that's a big help. Is there a top bracing position that is the go-to? I'm reading that there are three: standard, forward and rearward?

Thanks

Clay
"Facts seldom sway an opinion." - John Hall
"The difference between theory and practice is that in theory there is no difference." - Van de Snepscheut
tippie53
Posts: 7011
Joined: Fri Mar 03, 2006 7:09 pm
Location: Hegins, Pa
Contact:

Re: Dreadnought plans questions

Post by tippie53 »

your info may not be correct
The very first X brace dred was what they call forward shifted
used from 1934 to 1939
The rear shifted 39 into the late 40s
standard is where the angle changed and then there are variations of this in all I think Martin uses 27 different top X brace patterns

I personally like the forward shifted or 39 those are the only 2 I use
CadGuitarPlans used a lot of my tracings for the plans they used and were documented off old guitar

Greiller plans has good free plans

MacRosties are the next go to plan guy

AVOID
Antes
Over braces on the older plans can't say what the newer ones may be like
Gen One Georgia Luthers Same out fit
terrible plans and not authentic

So when using plans and you want to start making changes do so in small increments so you can see the cause and effect relationship
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
TEETERFAN
Posts: 342
Joined: Fri Sep 07, 2018 12:43 pm
Location: Kansas City, MO

Re: Dreadnought plans questions

Post by TEETERFAN »

John’s very correct. No need to deviate from accurate plans.
For my dreadnought kit, I used 1937 forward shifted plans and bracing thicknesses. I fabricated an elaborate deflection testing fixture and lo and behold, the top tested out perfectly with no tweeting necessary. I don’t feel I wasted my time with the testing, but good to know the plans/specs are very hard to improve on.
Kevin Doty
Kansas City
Morecowbell
Posts: 280
Joined: Thu Feb 21, 2019 10:51 am
Location: Fishers, IN

Re: Dreadnought plans questions

Post by Morecowbell »

Good to hear - I thought the forward shifted version sounded like the way to go but great to have experienced feedback. The StewMac plans are on the way!

Teeter - I'm interested in your deflection testing if you don't mind explaining what you did and what you learned?

Thanks,

C
"Facts seldom sway an opinion." - John Hall
"The difference between theory and practice is that in theory there is no difference." - Van de Snepscheut
tippie53
Posts: 7011
Joined: Fri Mar 03, 2006 7:09 pm
Location: Hegins, Pa
Contact:

Re: Dreadnought plans questions

Post by tippie53 »

I had used deflection testing but opted to something Wayne Henderson showed me
In a way how you tune your tops is individual and there really isn't any wrong way there is
your way.
So firstly I now tune my tops to get a C and my backs are tuned to a non harmonic of c

Now on deflection testing when I was taking engineering courses I though this may be the way to go

So love to see how others did this and keep it simple

I had a mount with a fixed span I think it was 21 inch

I would thickness the top to .125
then added a 3lb weight and measured the deflection
then 5 lb
and kept doing this till I got a defection along the grain of 1/8 in
this was my target weight

Now I braced my top and applied the target weight and measured the deflection.

Then I figured out the percentage of deflection to weight ratio

To be honest I find tuning to a C better for me.

The point is , what ever you decide to do will help with consistency
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
Post Reply