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Grellier OM Bracing Pattern

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Grellier OM Bracing Pattern

Postby Eric Knapp » Wed Apr 26, 2017 12:24 pm

Hello,

I'm working on my OM from the Grellier plans. It has been mentioned that I should consider not using the scalloped patterns in the plan. Are the positions of the braces OK? Are the end points in a reasonable position so I could start there and switch to tapered braces?

Grellier-OM-Bracing.png
Greller Bracing Pattern


I don't expect this first guitar to be perfect, it is a learning project. I want to get close and learn from it.

Thanks,

-Eric
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Re: Grellier OM Bracing Pattern

Postby Pat Foster » Wed Apr 26, 2017 4:16 pm

They'll work fine. On my OMs, I use 1/4" wide bracing, except for the UTB, but that's just me (and a few other, I believe).

Pat
I like to start slow, then taper off.
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Re: Grellier OM Bracing Pattern

Postby Mark McLean » Wed Apr 26, 2017 5:18 pm

Eric
I have 3 different versions of OM plans - and I would say that the overall layout of the bracing is consistent with those Grellier plans. I agree that tapered bracing, not scalloping, is the way to go.

Many people (myself included) would advise not to tuck the bracing into the rims in the lower bout. Taper them down to nothing just before they reach the linings (the X-braces and the transverse braces). This will give the top some more mobility and responsiveness. If you inlet everything into the sides you will have a very rigid box. However, in the upper bout you do want things nice and firm so the top end of the X, and the upper transverse brace do get notched into the linings and the sides. This is not a universally held opinion - and many older plans show the braces being inlet all around. You will need to form your own opinion about this (and many other things!).

mm
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Re: Grellier OM Bracing Pattern

Postby Eric Knapp » Wed Apr 26, 2017 8:27 pm

Pat Foster wrote:They'll work fine. On my OMs, I use 1/4" wide bracing, except for the UTB, but that's just me (and a few other, I believe).

Pat

Thank you, Pat. Those braces in the plans looked a little big to me but I didn't know if that instinct was correct.

-Eric
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Re: Grellier OM Bracing Pattern

Postby Eric Knapp » Wed Apr 26, 2017 8:33 pm

Mark McLean wrote:Eric
I have 3 different versions of OM plans - and I would say that the overall layout of the bracing is consistent with those Grellier plans. I agree that tapered bracing, not scalloping, is the way to go.

Many people (myself included) would advise not to tuck the bracing into the rims in the lower bout. Taper them down to nothing just before they reach the linings (the X-braces and the transverse braces). This will give the top some more mobility and responsiveness. If you inlet everything into the sides you will have a very rigid box. However, in the upper bout you do want things nice and firm so the top end of the X, and the upper transverse brace do get notched into the linings and the sides. This is not a universally held opinion - and many older plans show the braces being inlet all around. You will need to form your own opinion about this (and many other things!).

mm

Thank you, Mark. You are right, I need to form some opinions over time. Starting out I need to follow some advice from others more experienced than me. I think I'll do what you suggest here and just build something. I have lots of wood and after making tables and bed frames the wood in a guitar seems like almost nothing. It's all in the details. I'm getting closer, all I need is more time.

-Eric
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Re: Grellier OM Bracing Pattern

Postby Mark Swanson » Wed Apr 26, 2017 10:36 pm

I agree with the comments, it looks good to me too Eric. Don't forget to glue a slip of spruce over the lap join in the center of the X.
    Mark Swanson, guitarist, MIMForum Staff
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Re: Grellier OM Bracing Pattern

Postby Eric Knapp » Wed Apr 26, 2017 11:07 pm

Mark Swanson wrote:I agree with the comments, it looks good to me too Eric. Don't forget to glue a slip of spruce over the lap join in the center of the X.

Thank you, Mark. Little tips like that are like money in the bank. When I drive through GR towards Interlochen I hope to have something that sort of looks like a guitar to show you. :D

-Eric
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Re: Grellier OM Bracing Pattern

Postby Todd Stock » Thu Apr 27, 2017 6:56 am

I would consider building one scalloped/tapered and one tapered - getting either right is a challenge, and you'll learn more about the differences firsthand than you'll learn in a hundred online discussions. While the traditional 'Golden Era' OM tone is closely associated with scalloped and tapered bracing plans, the more modern, more top-driven tone of tapered or straight-braced instruments is worth exploring. If you can find some interior shots of Martin's 1945 dreads and 000's, you'll get a pretty good idea of where modern tapered bracing (aka, parabolic) originated. Being able to build both successfully should be your goal - you'll get clients that will want both tonal palettes, and the inability to generate one or the other restricts you to a smaller number of potential buyers. In some cases, the ask is for a particular sound, and it's tough to get either the looser, fuller base and scooped mids of the Golden Era or the tighter, more focused modern tone with just one tool in the toolbox.

Some builders feel the weakness in bending of the cloth-covered X-brace joint is a virtue with regard to traditional tone, but repair people will tell you that cracks and load-shifted stress damage is not unusual...I've seen a couple Montana Gibsons with pre-cracked X braces...easy reglue, but it illustrates the degree to which stress risers like a notch play into longevity. Understanding why the capped brace works is important - a cap needs to be fairly thick and fairly long to match stiffness with the notch-down side...for a rectangular 00 brace (.5" tall), a .100" by 2.4" cap would be needed. A thinner cap on a triangular sectioned brace would be closer in stiffness to a cloth cap than full-stiffness cap, but does a good job of changing the loads at the bottom of the notch to avoid downstream problems.
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Re: Grellier OM Bracing Pattern

Postby Eric Knapp » Thu Apr 27, 2017 9:56 am

Todd Stock wrote:I would consider building one scalloped/tapered and one tapered - getting either right is a challenge, and you'll learn more about the differences firsthand than you'll learn in a hundred online discussions. ...

That's a great bit of sage advice! Thank you, sir!

Todd Stock wrote:Some builders feel the weakness in bending of the cloth-covered X-brace joint is a virtue with regard to traditional tone, but repair people will tell you that cracks and load-shifted stress damage is not unusual...

I am to the point where I understand everything you are saying, this is good. Now I have to make it real. Thanks.

-Eric
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Re: Grellier OM Bracing Pattern

Postby Randolph Rhett » Thu Apr 27, 2017 9:59 am

I'm sure you are probably getting this already, but just build. You are sweating details you won't even be able to evaluate whether they made any difference. There is nothing overly magical and no real secret sauce to building a guitar. The thing is that it is a project with hundreds of small easy steps. The expertise is in the flawless execution of such a complicated workflow, not in some magical design element. Many variations on the basic design produce fine sounding and playing guitars. IMO the only way to make a good guitar is to make a dozen and to get good at the execution, not by fine tuning the design.
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Re: Grellier OM Bracing Pattern

Postby Eric Knapp » Thu Apr 27, 2017 12:13 pm

Randolph Rhett wrote:I'm sure you are probably getting this already, but just build. You are sweating details you won't even be able to evaluate whether they made any difference. There is nothing overly magical and no real secret sauce to building a guitar. The thing is that it is a project with hundreds of small easy steps. The expertise is in the flawless execution of such a complicated workflow, not in some magical design element. Many variations on the basic design produce fine sounding and playing guitars. IMO the only way to make a good guitar is to make a dozen and to get good at the execution, not by fine tuning the design.

I have gotten this message and fully endorse the idea. Sometimes I ask questions like this because I can't get to my shop very often during the school year. I want to keep learning even when I can't do anything. I have 3 weeks left and then I'll have a break for a few weeks before summer school. Then I hope to post daily progress of actually building, not just preparing and dreaming. I'm also quite content with the idea my first build will be a learning experience and not a great instrument. I intend to make more.

Thanks,

-Eric
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Re: Grellier OM Bracing Pattern

Postby Doug Shaker » Thu Apr 27, 2017 3:38 pm

I will add one more bit of advice. When you have the top built and braced, but you haven't started shaving the braces, make a habit of tapping the top at several places in the lower bout from time to time. And then flex the top a bit, see how stiff it is. At some point in the shaving, the top will change in sound significantly. You want to know when that happens. I can't say where you want to take that shaving/listening cycle - I'm only on my third acoustic. But it is a process, a sound, an evaluation system that you want to start be familiar with. You add too much stiffness (usually) when you glue the braces on and then you remove some of that stiffness when you carve the braces. You want to have a way of knowing where you are in that loosening process. Paying attention helps.
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Re: Grellier OM Bracing Pattern

Postby Eric Knapp » Thu Apr 27, 2017 5:19 pm

Doug Shaker wrote:I will add one more bit of advice. When you have the top built and braced, but you haven't started shaving the braces, make a habit of tapping the top at several places in the lower bout from time to time. And then flex the top a bit, see how stiff it is. At some point in the shaving, the top will change in sound significantly. You want to know when that happens. I can't say where you want to take that shaving/listening cycle - I'm only on my third acoustic. But it is a process, a sound, an evaluation system that you want to start be familiar with. You add too much stiffness (usually) when you glue the braces on and then you remove some of that stiffness when you carve the braces. You want to have a way of knowing where you are in that loosening process. Paying attention helps.

Thanks, I'm really looking forward to hearing that change. Someday I hope I'm near an experienced builder who can tell by feel and sound how a top is forming. I'm getting so close to doing this I'm starting to get really excited. There has to be a first build and it will mostly be for learning. That's ok.

-Eric
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Re: Grellier OM Bracing Pattern

Postby Eldon Howe » Sun Jul 09, 2017 7:36 pm

Thank you, Mark. Little tips like that are like money in the bank. When I drive through GR towards Interlochen I hope to have something that sort of looks like a guitar to show you.

Eric, if your passing through GR towards Interlochen I'm on the way as well love to see your work.
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Re: Grellier OM Bracing Pattern

Postby Eric Knapp » Sun Jul 09, 2017 8:15 pm

Eldon Howe wrote:Thank you, Mark. Little tips like that are like money in the bank. When I drive through GR towards Interlochen I hope to have something that sort of looks like a guitar to show you.

Eric, if your passing through GR towards Interlochen I'm on the way as well love to see your work.
Eldon

Hi, Eldon.

Are you going to the Chapman Stick Workshop? Well, I can't go now. My health won't support a trip at this time. I'm very upset about this because I've been to all the Stick workshops at Interlochen. I love going there, it is kind of a retreat for me. I hope to go again some day.

Thanks for thinking of me.

-Eric
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Re: Grellier OM Bracing Pattern

Postby Eldon Howe » Mon Jul 10, 2017 4:28 pm

No too busy.
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Re: Grellier OM Bracing Pattern

Postby Kevin Looker » Fri Jul 14, 2017 8:03 am

I'm building my 4th OM from those plans. This one will be tapered bracing.

The first 2 were scalloped like the plans because I didn't know what else to do or what to change. They both sounded good from the start, nothing spectacular but in no way bad.

The 3rd I didn't scallop as much. I thought it sounded stiff, dull & uninteresting. I gave it to my daughter who played it periodically. About a year after I gave it to her I picked it up and it sounded great! It wasn't super sensitive to a light touch but could be played much louder than the other two & encouraged you to get into it - great for a hack strummer like myself.

So the 4th is tapered. My last was an L-00 with tapered bracing & I love the sound it has - very focused with excellent note separation. I realize L-00's & OM's are very different animals not to mention other factors but I enjoy the process.
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Re: Grellier OM Bracing Pattern

Postby Mike Conner » Fri Jul 14, 2017 12:43 pm

Randolph Rhett wrote:I'm sure you are probably getting this already, but just build. You are sweating details you won't even be able to evaluate whether they made any difference... .


Eric,
Randolph's comments are good in that the best thing to do is just go ahead and build. You will make mistakes and then work through them. That being said, I am an engineer and strangely enjoy the "building first in my head" part of the lutherie experience. You are asking some detailed questions that will inform your understanding and direct your thinking as you approach those steps. That has been my approach also, but have pushed niavely ahead into the "unknown" when needed.

In the end you will have a guitar that sounds like a guitar. Maybe it will be average, and maybe it will be spectacular. I was delighted when my first builds didn't just sound like a cardboard box and stayed in tune! The point is to have some fun out of it. And yes, I am just geeky enough to enjoy researching, discussing and documenting the details almost as much as the building.
//mike
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Re: Grellier OM Bracing Pattern

Postby Karl Wicklund » Sat Jul 15, 2017 11:16 am

I'll second the advice of "just get building."

But...

When I get undertake a new project, I have a lot of trouble just thinking through it. I like to talk through it. Which I guess is thinking through it out loud. It always takes me a certain amount of conversation to get my mindset ready.

In other words, once my shop is a bit more put together, look for lots of simple questions from me!

Keep it up, Eric!
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