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Hey all,

Want some feedback on this bracing -- for a Ditson build.
Lower bout is 15" if I remember right.

This is my last chance to tinker before the back goes on.... so I want some opinions.

Specifics:
Building per a print... except I think the print is too heavy...
I went about 0.100" for the top thickness.
X and Tone bar are 1/2" x 3/8"
Finger bars are 1/4x1/4

A braces are 3/8 x 1/4
and the *Stinkin' huge* Mahogany UTB is 1/2x1/2

X legs are triangle above the X and volute/swoopy triangle below.
The Tone Bar is volute/swoopy triangle shaped, and slightly reverse tapered (Thicker at the rim end.)





Questions:
How far up do the Upper X legs need to go at full height... Mine are full height up to about 1" from the linings. I have been poking in Factory guitars, which seem to be about 1/8" tall for 2+" before the linings -- like they drop off at the bottom of the sound hole.

Should I give it a little more scallop?

General impressions -- Too heavy?

Thanks

John

I cant comment on the 1/2 x3/8 brace, as I have never ever seen nor used one .. I would have gone 1/4-5/16 by .500-.580 tall .. depends on string gauge some there. The 1/2 by 1/2 is OK, I use .400 by .590 for the UTB these days, radiused.

I also had no idea the X was asymetrical .. at least it looks that way in yours. I also see no need to have that much brace (height) in a tone bar so close to the guitars edge - its stiff from the rim anyway. I taper mine down quite a bit.

If I were you though, the one thing I would not leave is that point sticking on the bridge plate ... in my mind I can already see it down the road a few years (maybe sooner) where that will telegraph right thru the top from the rear of the bridge pulling up - tapering that corner to nothing is the easy way to prevent that from happening - or change out the plate. I also would have had the tone bar touch the X.

_________________
Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

Right.... Asymmetrical X...
That was a slight change on my part.
Wanted to see how it would work out.
It is about 1/2" off at the rims from the other side.

The "Old" distons didn't use an A-brace on the upper bout. That is something I am also trying out.

I can trim off the corners off the bridge plate -- don't want it poking out in a couple years.

Here's my current body dimensions:
Width
Upper bout 10 3/4"
Waist 10"
Lower bout 14"

Depth
Upper bout 3 1/4"
Lower bout 4"

so it's about the size of an O size or so.

Thanks

John

Ok,

I loosened it up a little.

The start of taper/scallop on the ends of the X and the tone bar near the rim are now farther from the rim.

I touched the scallop a wee bit....
and tried to round off and taper down the Bridge Plate corners.





Opinions?

Thanks

John

Oh .. something I didnt notice before .. your tail block is way huge IMO. Only needs to be 5/8 to 3/4 thick (I actually use a 1/2 inch piece of baltic ply now). The other thing to do is to trim the top (and back) edge, back at an angle so that the glue area on the top of the block is the same width as your kerfing. The same thing will happen here over time, the block shape will telegraph thru the top. So if you make it kerfing width where it glues, that wont happen.

Better on the bridge plate as well .....

_________________
Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

I am not sure how much I can do about Mr. Giant Tailblock on the soundboard end -- it is already glued down..... but I can try to pare it down some towards the back.

I am guessing that the back is usually not the problem with telegraphing, though.

I am surprised that no one had any Brace comments.... It is hard to tell if "No news is good news" or people just don't want to break bad news......

Like....
Is the light scalloping on the X legs worth the trouble with this small size guitar?
Is the light scalloping on the X legs enough -- are they tapered down enough to behave properly?

Otherwise, are the braces light enough? How about right around the X?

Thanks

JOhn

Until Bruce Dickey mentioned this to me other day, I had never heard of Ditson. That looks like the same bracing used on a Dyer Harp guitar.

The bridge plate is smaller. I used that asymmetrical x brace in my current build. Not sure I will do it again... at least I will modify the bridge plate... too darn big (yours looks fine)

I for one would appreciate any historical information on Ditson.

Mike

Mike,

Basically, I understand that the Ditson is a precursor to the modern day Dreadnought. I have heard it called a "Baby Drednought" because of the shape.

They were built by Martin for the Oliver Ditson Company from like 1916 - 1920 or so.

Apparently, Mr. Ditson "Designed" the "Wide Waisted" shape....

There were 3 sizes -- #1, #11, and #111 -- The #1 was like a 1 sized Martin, the #11 was like a OO, and the #111 was the biggest guitar you could get in production at that time... Apparently, the D-18 design was roughly patterned on the 111 model. Their "Style" numbering apparently was that the 1 was most plain going up to 3 being most fancy -- so a 3 is a 1 size, extra fancy.... and a 333 is a 111 size with all the doo dads.

Mine is the 11 model.... Recently, this pattern seems to have picked up the name Ditson "Grand Concert".

Martin is currently doing a Reissue of the bigger 111. Pretty pricey.... but it is a special issue Martin and probably plays great.

Hope this helps some.

John

I don't know much about the Ditson scheme but I have issues with a tone bare that terminates bare ended. To me it is neither structurally supportive nor provides a path of energy dispersal because it is not tied into to the X-brace nor the bridge plate. It appears to be an after thought.

1) I'm troubled by the appearance of the bridge plate. The bridge plate should be in intimate contact with the lower legs of the x brace.

2) Once that's done, the tone bar should contact the lower x brace leg as well as the bridge plate.

3) On the upper x brace legs, I'd start a taper (not a scallop) about 1" from the X

4) I agree with Tony on the massive tail block...I also use 1/2" baltic birch ply.

Please don't take these suggestions personally...they're meant in the spirit of your original question and it's how we all learn. Kudos for having the intellectual courage to ask!

_________________
JJ
Napa, CA
http://www.DonohueGuitars.com

John, I think you’ve done a great job of taking the mass down on your braces. They look fine to me. As long as you taper the bridge plate, I don’t see a problem there.
Why are you guys so concerned about the bare ended termination of the tone brace at the bridge plate? Isn’t it close enough to still do what it is supposed to do? It still makes a connection to both the plate and the X leg by its proximity. No?
A little less mass at that spot but I don’t see the fuss.
Maybe I'm wrong, it wouldn't be the first time.
In any event, John, if it bothers You, It is fairly easy to shave it out and make another before you glue the back on.
Looking Good!

_________________
Wade
Nashua, NH
http://www.wadefx.com

IMO proximity is not the same as connected. think of it in both a structural and energy transfer since. neither connection is made it is not tied or butted to anything with the exception of a fine point at one corner of the bridgeplate.

And why do you think I am making a fuss. i gave a personal evaluation (a critique) which was asked for by John. That statement sounds like it fine to give a critique that 100% glowing but please no negitives????? come-on It is a critique for goodness sake.

Sorry Michael, I guess I should have put a smiley face after that statement.
I guess I was trying to provoke a more detailed response. (and thanks)
I didn't intend to sound negative. My Bad.

_________________
Wade
Nashua, NH
http://www.wadefx.com

No offence taken. From my first reply I said that the tone bar ending attached to neither the X brace nor the bridge plate provide neither a good structural support nor a good path for energy transfer. This is my opinion and is to be taken as such and no more. In my minds eye it seems that a terminal node in free space like the tone bar is would act more as a baffel, daming the energy from the bridgplate than as a trasmitter convaying energy to the lower bout, because of the terminal node in free space. I can be wrong here. But I have doubts that I am wrong.

What I am really trying to avoid here is the "Sure guy, go ahead and build it and tell us how that goes" sort of response that ends up producing a Dead Sounding Guitar Like Object. I have seen people end up with crazy heavy and weird designs because no one would step up and say "WTF are you doing?" I read a post on another board where a fellow was going to inlet every single brace in a Stew Mac Kit -- He was using an 1/8" thick nice stiff top and full size kit braces.... and was going to inlet every brace into the X and tuck every brace into the linings.... and folks just kept saying "Sure, go ahead and tell us how it works out" This sort of advise may be fine if you are building a coffee table or a bookshelf.... but it would make a terrible guitar.

I really do appreciate the suggestions and Opinions and Critiques.... even the Negative ones... I am still pondering what I can do to that giant tail block... If I had one of those Frank Ford special super duper saws.... I could just push the blade on down there and whack it in half.... but I have hand saws and chisels and a router. I am worried about sticking a hole in the soundboard if I try to cut that block down.

I am trying to decide whether to chisel out the tone bar and butt it into the X or just go with it. Should I retaper the tone bar to thin it down at the lining end? Not sure either. The concern I might see is that the gap could leave it too flexy in that one spot.... and prone to doing all its flexing right there and nowhere else.... leading to bad things. Does it actually do that, though?

I honestly haven't built enough to know whether there is a difference in sound between braces butted into the X and free ended braces (Like tone bars and finger braces.) I know there are people here who have built enough to have an idea, though.

One thing I do have 1st hand experience with is a "Stiff centered" guitar -- and I guess I have to say that this build is probably trying to compensate for "Too stiff in the center" on the last one. That is why I purposefully left the Tone Bar away from the X... and also why the tone bar has a reverse profile taper (heavier towards the lining end) I was actually going to leave about a 1/8" gap between the Bridge plate and the X -- but decided against it for no particular other reason than convention.

Was this a good idea? No idea. Maybe it wasn't.

If anyone has tried it out butting vs not butting Tone Bars and Finger braces -- what was the difference you saw?

Thanks

John

No not a good idea the tone bar is taking energy from the x brace and transmitting it to the lower bout. Some attach to both the bridge plate and the x brace some only the X brace. IMO by having the free end out there short of the x brace the tone bar will moderate (reduce) the energy not help carry.

A given amount of stiffness in the bridge area is a good thing not bad. If the bridge plate area is too elastic then the energy is lost to the motion of the top and you loose tonal focus and volume

Ah ... didnt know it was already glued (top/rim) .. even still - I would take a chisel, and possibly a small saw if you can, and take the tail block down at the rim/top joint area ... cut it at a 45, aiming for the kerfing and then chisel that chunk out - carefully. It can be done.

_________________
Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

Hi Truckjohn,

I'm curious were you got your deminsions for your Ditson? I just completed one awhile back and have just started another. I got a rough print(plan) from someone on the net and my measurements are diferent from yours.

Its for the Ditson GC:
Upper bout:10"
waist:8-3/4"
lower bout: 13-1/2"

As for your bracing I'm not experienced enough to say.....

Jeff

Jeff,

I posted my finished dimensions. I just measured the guitar body I ended up with.
I think my *plan* dimensions are pretty close to yours.
Mine is also about 1/2" shorter than the plan --
Apparently, that sort of thing happens when it expands a bit in the belly and waist....
(Seems like the same thing happened to me somewhere along the line)

Thanks

John

I understand about the belly and waist! LOL11

I have never actually played an original Ditson from the early 1900's. I have seen a couple though. The closest thing I've played/seen was a Washburn Ditson style dreadnaught from approximately the mid 30's. It belongs to Robert Bowlin and is a great guitar. Neither he nor I have ever seen one like it. When I played it it needed a neck reset which I think Robert just recently did himself. The guitar was awesome. Light in weight, round and fat like a pig to hold and just a pleasure to play with the baseball bat sized neck. I'm sure yours will sound great. I've been considering building a prototype for myself. Best of luck and looks good so far.

SR

_________________
"We might not be big but we sure are slow"

With the infinite variability from one piece of wood to another, it's tough to make any educated
call from photos. A wider, higher piece of Spruce can sound as good or resonant as a much lower,
narrower piece as long as it's light and very resonant...and vice versa. So, the real proof is in the
hearing as the braced top is handled and tapped.

I will say, though, that 3/8" wide is much wider than I would ever recommend going with any of
the top bracing simply because it's possible to achieve the same structural rigidity and integrity by
going a little higher and minimizing the footprint of the brace.

Your tone bar should have at least made contact with the lower leg of your "X" brace. Some guys
like to tuck them in or insert them into the "X" brace, but that's a whole other issue. Making contact
just contributes to the overall functionality of the bracing as a system that collects, directs and
distributes the vibration created by the played strings. The gap between the tone bar and "X" brace
also presents a small breach in the strength offered by the whole brace system on a structural level.

Regards,
Kevin Gallagher/Omega Guitars

Are you guys saying that you actually join the lower tone bars to the x-brace or just but it up against it? FWIW I use a similar bracing pattern for my smaller guitars with the single tone bar though I use two finger braces. My lower tone bar buts to the X-brace but I still feather the edge and the guitars sound great.

Just for the record, the original Ditson series of guitars (c.1916) were fan braced. This included the very small I, the larger II and the largest III which is the same size as the present Martin 12 fret Dreadnought. These also came in style 2,22,222 and 3,33 and 333 designations as well as a very few which were built in standard Martin styles. I've seen them in styles 21, 30 and of course the famous "baby" D-45. I've owned both a 1 and a 2, the 1 was later bought and used by Sting.
A few of the later III guitars were made in the 20s and I think these were X braced as is reasonable I think to brace this design nowadays for the sake of practicality.
The smaller two sizes (there actually exists one size "5" of this shape as well as well as a series of Martin ukes with this shape) should get X braces at 1/4" widthwhere the larger one is better with 5/16". 3/8" is rather large and is what Martin used for their 60's 12 strings with this body shape.......you can always shave the height of these down a bit to approximate the stiffness of a a smaller brace.
All of this "energy transfer" between the braces talk I think is confusing. It is much better to think of the overall stiffness vs. flexibility of the top and to what extent (and with what pattern) one can accomplish a stiffer or more compliant top. Depending on the sort of response that is desired.

I was hesitant on the 3/8" wide braces all around.... I know the "Standard" OLF OM braces are 1/4" wide -- so the 3/8" braces are about 1.5X stiffer... which is a whole bunch.

I tried to compensate for this with the gouge -- scooping out material so the brace had a wider but very thin footprint. If nothing else, this should help keep them from telegraphing.... which I really don't think would have been a problem anyway with this top thickness.... If the top was like 0.080" thick... maybe it would help.

Thanks for the advise on this.

John