Official Luthiers Forum! :: View topic - Shaving Braces Through the Soundhole

Michael--

Do you have any other perspective photos of your voicing frame? I have the Somogyi books, so I know the idea behind it, but it would be great to see what yours looks like.

Did you make the form to accept a doomed top or are you building a true flattop?

Nice Michael! I assume it's that thick to replicate the interior volume of the box when seated on a flat surface. I have a similar rig but without that feature. It is just for deflection testing once braced.

New username, same ole Pat Macaluso!

Has anyone found tools that make this task easier?

I have a set of Boone planes, various chisels and some short stubby carving tools.

I was considering a small rasp, something short enough to get through the hole but long enough to reach the lower ends of the braces & still have good control.

Thanks.

klooker wrote:

Hi Kevin,

My apologies for unintentionally hijacking your thread.... oops_sign

Best, M

Pmaj7 wrote:

Hi Pat,

It's really just how I learned to do it when hangin with Ervin. You can check it out when we can coardinate a visit. I'd like to see how you are doing you braced testing.

M

The Gore book goes through lab grade quality instructions on how to select a piece of wood using all kinds of equipment and so on. And then once the box is assembled it instructs you to thin out the perimeter? That seems to me to completely nullify all your hard work in getting to that point. It's always bothered me... You go through all that trouble to build a scientific guitar and then resort to good old school methods and thin the edges?

Author:	klooker [ Fri Oct 26, 2018 7:44 am ]
Post subject:	Shaving Braces Through the Soundhole
Has anyone found tools that make this task easier? I have a set of Boone planes, various chisels and some short stubby carving tools. I was considering a small rasp, something short enough to get through the hole but long enough to reach the lower ends of the braces & still have good control. Thanks.

Author:	Michaeldc [ Fri Oct 26, 2018 8:03 am ]
Post subject:	Re: Shaving Braces Through the Soundhole
I saw these the other day. The price is right! http://www.leevalley.com/us/Wood/page.a ... at=1,42524 M

Author:	jfmckenna [ Fri Oct 26, 2018 8:05 am ]
Post subject:	Re: Shaving Braces Through the Soundhole
I use my rounded Boone Plane and sand paper.

Author:	Clay S. [ Fri Oct 26, 2018 8:49 am ]
Post subject:	Re: Shaving Braces Through the Soundhole
Another possibility is one of these: www.ebay.com/itm/VINTAGE-WOODCRAFT-SQUI ... hs:rk:5:pf: The Stanley version is the 100 1/2 squirrel tail plane (radiused sole), and I think Lie Nielson also makes a version of it . It should be small enough to work inside the guitar.

Author:	Pat Foster [ Fri Oct 26, 2018 10:11 am ]
Post subject:	Re: Shaving Braces Through the Soundhole
Kevin, I tried using finger planes and rasps, but discovered this and never looked back, been touting it for years. It's a cheap hobby Zona spokeshave with the ears cut off. I usually pull it rather than push it, with my index and middle fingers as guides to keep it on the brace. The iron isn't the best quality steel, but it takes a reasonable edge. Drawback is lack of reach for working inside a closed box. I use it for all my brace trimming, before and after the box is closed. Attachment: Screen Shot 2018-10-26 at 7.53.09 AM.png Attachment: xactospokeshave.jpg Attachment: DSCN7334a.jpg

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Author:	philosofriend [ Fri Oct 26, 2018 10:44 am ]
Post subject:	Re: Shaving Braces Through the Soundhole
I use a curved chisel, the blade is about an inch wide with about a five inch radius. It has a stubby wood handle that is a large part of what makes it easy to use.

Author:	Pmaj7 [ Fri Oct 26, 2018 11:53 am ]
Post subject:	Re: Shaving Braces Through the Soundhole
1 inch stubby chisel and the small curved bottom bronze plane from LMI. New username, same ole Pat Macaluso!

Author:	meddlingfool [ Fri Oct 26, 2018 12:01 pm ]
Post subject:	Re: Shaving Braces Through the Soundhole
Boone planes all the way!

Author:	Alan Carruth [ Fri Oct 26, 2018 1:55 pm ]
Post subject:	Re: Shaving Braces Through the Soundhole
One of the advantages of 'tap tone'/'free plate' tuning is that you do all that stuff before the box gets closed, when it's easier to get at things!

Author:	klooker [ Fri Oct 26, 2018 5:59 pm ]
Post subject:	Re: Shaving Braces Through the Soundhole
Thanks for all the replies folks!

Author:	jfmckenna [ Fri Oct 26, 2018 8:25 pm ]
Post subject:	Re: Shaving Braces Through the Soundhole
I've always been one to tweak parameters after the box has been assembled. Of course we should do our best to get it right from the get go but.... I have an issue with free plate tuning and after reading the Gore Gillet books, an issue with that too. First off, I absolutely agree that finding some scientific based method to building is a great idea. If anything becasue you pick a method, stick to it, observe results, wash rinse and repeat. I use deflection testing for that very reason. You really start to narrow things down that way, no doubt about it. But.... A free plate is free. Attach it to a body and the equation becomes so much more complicated. None the less it's a baseline, like deflection is and that's great, but you still might have to reach in sound box to change things... Perhaps the master does not IDK - not there yet. The Gore book goes through lab grade quality instructions on how to select a piece of wood using all kinds of equipment and so on. And then once the box is assembled it instructs you to thin out the perimeter? That seems to me to completely nullify all your hard work in getting to that point. It's always bothered me... You go through all that trouble to build a scientific guitar and then resort to good old school methods and thin the edges? So.... I still like to build on the brink of lightness but just in case a tad bit heavy... Maybe... So that it can be tweaked. Measure twice cut once kind of thing.

Author:	Greg Maxwell [ Sat Oct 27, 2018 8:01 am ]
Post subject:	Re: Shaving Braces Through the Soundhole
Shaping the braces with future tuning in mind is part of the process for me. My X braces are pyramided and tapered, and making a sharp pyramid on top makes tuning them through the sound hole much easier. Scalloped or rounded braces are a lot tougher to carve. I tune my tops to the final target resonance after the guitar is strung up and has settled in for a week or two.

Author:	Michaeldc [ Sat Oct 27, 2018 8:25 am ]
Post subject:	Re: Shaving Braces Through the Soundhole
+1 for the scientific approach For me, free air testing without some kind of signal analyzer never made sence to my ears. I personally can't tell what's happening when I make a change to a brace. I know some folks are very successful using this approach. My current process starts with Gore plate testing using my laptop, the recommended free analyzing software, and a spreadsheet (Thanks to John Parchem for setting me up and explaining how it worked!). I then thickness the plate to the target deflection, install the rosette, install the braces and bridge plate, and then place upside down in the appropriate voicing frame (that's what I call it anyway) which I learned from Somogyi. Here is a shot of my 00 pattern clamped in the frame ready to start carving. Using this system I'm able to clearly hear what's happening when I make a change. The frame is made from 7 layers of 3/4" partial board glued together. The final layer is obviously removable for clamping. I've only had to tweek the braces once after closing the box and that was years ago. If you hate making jigs and fixtures you will hate my way of coming at it. I personally love making tools! I'm always amazed at how many ways one can come at this sport and still end up with excellent results! M

Author:	doncaparker [ Sat Oct 27, 2018 10:51 am ]
Post subject:	Re: Shaving Braces Through the Soundhole
Michael-- Do you have any other perspective photos of your voicing frame? I have the Somogyi books, so I know the idea behind it, but it would be great to see what yours looks like.

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Author:	Ruby50 [ Sat Oct 27, 2018 12:52 pm ]
Post subject:	Re: Shaving Braces Through the Soundhole
Michael Where do attach the signal analyzer? What do you strike the plate with? Where do you strike the plate? It seems the goal is to make the perimeter of the plate as rigid as possible - are you accurately duplicating the condition once it is glued to the rim? Why exclude the upper bout from the testing? Can you explain what changes you are looking to make? Very interesting Ed

Author:	Michaeldc [ Sat Oct 27, 2018 1:26 pm ]
Post subject:	Re: Shaving Braces Through the Soundhole
doncaparker wrote: Michael-- Do you have any other perspective photos of your voicing frame? I have the Somogyi books, so I know the idea behind it, but it would be great to see what yours looks like. Don, Here's another shot. The inserts are 1/4-20 and are soaked in thin CA to give the partial board a bit more integrity. I made a template and used a guide bushing and a router to accurately cut the parts. M

Author:	Pmaj7 [ Sat Oct 27, 2018 6:54 pm ]
Post subject:	Re: Shaving Braces Through the Soundhole
Nice Michael! I assume it's that thick to replicate the interior volume of the box when seated on a flat surface. I have a similar rig but without that feature. It is just for deflection testing once braced. New username, same ole Pat Macaluso!

Author:	Barry Daniels [ Sat Oct 27, 2018 7:37 pm ]
Post subject:	Re: Shaving Braces Through the Soundhole
Did you make the form to accept a doomed top or are you building a true flattop?

Author:	Michaeldc [ Sat Oct 27, 2018 7:58 pm ]
Post subject:	Re: Shaving Braces Through the Soundhole
Barry Daniels wrote: Did you make the form to accept a doomed top or are you building a true flattop? Barry, It's made flat, though my tops are braced in a dish. 25' and 30' depending on the model. My tops are very thin in most cases. About .095" for stiff Sitka to .115" for a recent carpathian 00. I find the braced top easily deals with the flat nature of the form. Best, M

Author:	Michaeldc [ Sat Oct 27, 2018 8:03 pm ]
Post subject:	Re: Shaving Braces Through the Soundhole
Pmaj7 wrote: Nice Michael! I assume it's that thick to replicate the interior volume of the box when seated on a flat surface. I have a similar rig but without that feature. It is just for deflection testing once braced. New username, same ole Pat Macaluso! Hi Pat, It's really just how I learned to do it when hangin with Ervin. You can check it out when we can coardinate a visit. I'd like to see how you are doing you braced testing. M

Author:	Michaeldc [ Sat Oct 27, 2018 8:06 pm ]
Post subject:	Re: Shaving Braces Through the Soundhole
klooker wrote: Has anyone found tools that make this task easier? I have a set of Boone planes, various chisels and some short stubby carving tools. I was considering a small rasp, something short enough to get through the hole but long enough to reach the lower ends of the braces & still have good control. Thanks. Hi Kevin, My apologies for unintentionally hijacking your thread.... Best, M

Author:	klooker [ Sat Oct 27, 2018 11:34 pm ]
Post subject:	Re: Shaving Braces Through the Soundhole
Michaeldc wrote: klooker wrote: Has anyone found tools that make this task easier? I have a set of Boone planes, various chisels and some short stubby carving tools. I was considering a small rasp, something short enough to get through the hole but long enough to reach the lower ends of the braces & still have good control. Thanks. Hi Kevin, My apologies for unintentionally hijacking your thread.... Best, M No, not at all. I'm actually very happy at where this thread has gone - we're getting at the underlying issue.

Author:	Pmaj7 [ Sun Oct 28, 2018 9:26 pm ]
Post subject:	Re: Shaving Braces Through the Soundhole
Michaeldc wrote: Pmaj7 wrote: Nice Michael! I assume it's that thick to replicate the interior volume of the box when seated on a flat surface. I have a similar rig but without that feature. It is just for deflection testing once braced. New username, same ole Pat Macaluso! Hi Pat, It's really just how I learned to do it when hangin with Ervin. You can check it out when we can coardinate a visit. I'd like to see how you are doing you braced testing. M Sounds good! I don't have a braced top to put in there right now, but basically it's just the outside mold with one extra layer screwed on top (similar to yours) to hold the soundboard on tight. There are little notches in it where the braces exceed the pattern. I don't have the simulated Air volume like yours does and I do not analyze the frequency, just a deflection test. New username, same ole Pat Macaluso!

Author:	Dave m2 [ Mon Oct 29, 2018 3:26 pm ]
Post subject:	Re: Shaving Braces Through the Soundhole
Michael I'm very interested by your system. You say that you follow G&G's method then after bracing finish the process in your voicing jig. But what do you actually do at this point? Are you looking to set the top resonances as per G&G? Or something else? Having completely rigid sides and a fixed top/side joint presumably means this setup differs from the final assembly of the guitar. (beautifully clean work there by the way) Dave

Author:	Trevor Gore [ Tue Oct 30, 2018 6:28 am ]
Post subject:	Re: Shaving Braces Through the Soundhole
jfmckenna wrote: The Gore book goes through lab grade quality instructions on how to select a piece of wood using all kinds of equipment and so on. And then once the box is assembled it instructs you to thin out the perimeter? That seems to me to completely nullify all your hard work in getting to that point. It's always bothered me... You go through all that trouble to build a scientific guitar and then resort to good old school methods and thin the edges? What all the plate and bracing testing does is enable you to compensate for the variability in the top, back and brace wood. That testing does not intrinsically "know" what sort of chassis you are going to glue your top or back to. And when you glue it down (and then stick a bridge on) we all know that that changes everything. If you glue the top to the exact same chassis every time (same shape, same total mass, same air volume, same back stiffness, same back resonance, same lining mass and stiffness, same lining glue area, same side stiffness, etc., etc., etc.) you would get the same result every time. But we don't glue to the same chassis every time, because we can't replicate those things to the necessary degree of accuracy. But if you compensate for the variability in top and back panels by using the methods in the books you can get close enough to trim the resonances to your targets without too much trouble, and the edge thinning that John mentions above is one (of numerous) of those techniques that I use to do that. Remember also that the contemporary methods of construction that I describe in the book use carbon fibre/wood composite braces, which pretty much precludes any brace shaving activity, so knowledge of other methods of resonance tuning is essential. What happens when you don't take material properties into account was illustrated very well in a paper that Michael French published in American Lutherie. He showed that you could expect up to 10Hz spread in main air resonance and 20Hz spread in main top resonance if you build just to dimensional tolerances (rather than acoustical tolerances). That range means there will be some very different sounding guitars. Of course, if you like to be surprised by what you have when you're finished, just build to a set of physical dimensions. But if you're building for paying customers, managing their expectations can a challenge.