OLF SJ Bracing Pattern

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RnB
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OLF SJ Bracing Pattern

Post by RnB »

I've had a set of OLF SJ plans for quite some time & want to move forward on a build w/ them. Doing some research here & on the OLF, it seems the bracing pattern orig laid out by the architect (M Payne) comes into question, esp w/ respect to the X-brace & the tone bars being so apart from each other. Seeking a bit of advise here as to how one would go about rectifying the bracing layout.

In one Thread, I saw that Tippie had built an SJ & moved the bracing around more to his liking. Would this be, spreading the X-brace, so it's more open and so it is not so close to the 'upper transverse brace' ? Seems like the pattern for an OM w/ 1/4'' bracing would be the better way to go, since the dimensions (body widths) for the SJ & an OM are relatively close...?

edited to add pic...
Image
Last edited by RnB on Fri Jul 07, 2017 9:10 pm, edited 1 time in total.
Diane Kauffmds
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Re: OLF SJ Bracing Pattern

Post by Diane Kauffmds »

I'm sure John will clarify what he did. I know that the x-brace can be forward or backward shifted, depending on what you aim to accomplish.

I had a project guitar that I replaced the top on, as well as the 00 that I just built. The project didn't conform to a OM or 00, but fell between. I spread the x-brace so that it fell ~ 1 1/2" from the bottom of the soundhole. In the case of the 00, I had a plan, but wanted to forward shift the brace towards the hole, to increase bass response. In this case, the ends of the x-brace would have overlapped the transverse brace, so I spread the brace to make it fit better and shifted it forward 1/2" so that it fell 1" from the bottom of the soundhole. The project guitar had a well rounded voice. The 00 has a rich, well rounded voice and has excellent bass response.
Diane Kauffmann
Country Roads Guitars
countryroadsguitars@gmail.com
tippie53
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Re: OLF SJ Bracing Pattern

Post by tippie53 »

I didn't like the brace layout. I think it sounded too tight. I opened the X brace to 98 degrees. Moved the tone bars more into the martin position. That was more pleasing to my ear.
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
RnB
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Re: OLF SJ Bracing Pattern

Post by RnB »

Thx J & D...

John,
Did you keep the center-point of the X-brace as in the plans or move it closer to the soundhole edge (fwd-shifted) ?

Since the body's slightly longer/lengthier than an OM, it has has more open acreage below the bridge locale. Seems it would not make sense moving the X-brace up 1" from the soundhole & have all that open space below bridge on the top. Plus, taking away bridge support. Just guessing here, but wouldn't that make for tubby tone...?
tippie53
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Re: OLF SJ Bracing Pattern

Post by tippie53 »

yes I did it more Martin style. I moved the X braces up but kept the bridge plate where it was
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
nkwak
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Re: OLF SJ Bracing Pattern

Post by nkwak »

I did the MJ and was told to increase the angle to 100 degrees. I kept the junction point of the X brace in the same location but also tapered the lower bout ends of the braces to end just shy of the kerfing.
~ Neil
Diane Kauffmds
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Re: OLF SJ Bracing Pattern

Post by Diane Kauffmds »

I did pretty much what John did. I spread the brace to 98°on the 00, and forward shifted toward the hole.

I used 100° on the project guitar top, and the X was ~ 1 3/4" from the hole. I had no guitar plans in hand, so I searched images on the Internet and extrapolated enough info to draw a plan. It ended up sounding very good, but I think I prefer forward shifted.
Diane Kauffmann
Country Roads Guitars
countryroadsguitars@gmail.com
RnB
Posts: 210
Joined: Wed Jan 25, 2012 1:44 pm
Location: Bay Area

Re: OLF SJ Bracing Pattern

Post by RnB »

Yes, I'm still here :-)

Hopefully getting ready to move forward on this OLF SJ build. Plagued by health issues, family & laziness (actually playing guitar) for some time, but I'm feeling much better.

Tippie:
I didn't like the brace layout. I think it sounded too tight. I opened the X brace to 98 degrees. Moved the tone bars more into the martin position. That was more pleasing to my ear.
I laid out a new template for the SJ w/ a 98 degree X-brace, FS - 1" from the soundhole. Wasn't exactly sure where the tone bars should be placed? Have a Martin Jumbo top I used for comparison & came up with this. ...a-la Martin style. I did not make any adjustments to the bridge plate & bridge & left them in same position as plans. By all accounts, the neck should fall into place.

Think I can minimize (trim down) the bridge plate some...?

SJ
Image

Martin J top
Image
nkwak
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Re: OLF SJ Bracing Pattern

Post by nkwak »

Looks good, but I'm learning that there's a balance between following what others have arrived at through methodology and when sometimes you have to call an audible in order to overcome a mistake. On my second build I went a little too thin with the thickness sander and the top was at the very limit of stiffness. I paid Tim McKnight a visit in his workshop and his solution was this.

Image

He advised me to taper the braces only, no scalloping and keep as much mass on the main X brace as possible. The end of the bridge plate is rounded to prevent potential bridge shear and the edge is profiled to a rounded edge to prevent splitting. The X is 100 degree wide and the junction is 1" back from the soundhole.
~ Neil
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