Official Luthiers Forum!

Saw a couple videos of some builder who do so and was curious about different takes. Certainly Martin Gibson Taylor do so with custom CNC rigs but was wondering how many here might pre-carve knowing that some braces will get to a certain shape every time before final voicing/carving?

_________________
Thank You and Best To All

It's not carving as such, but I pre-profile the upper face brace, the tone bars, and the two braces on each side of the sound hole for the top, and the upper two transverse braces for the back. I use a jig run through my drum sander that makes it fast and consistent. All the actual carving I do is done after the braces are glued on.

_________________
Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

I shape the bottoms of braces where they glue to the soundboard and often round the top edge with a roundover bit before gluing. After they are glued they are carved and reshaped to what I think will work best. Most factories and even some hand builders preshape their braces. "Tuning " the soundbox is the hand built guitar's supposed advantage over the factory built item. How well it is done is where the wheat separates from the chaff.

I radius the bottom of my braces. All carving and shaping are done after braces are glued to the top/bottom plates.

_________________
Steve Smith
"Music is what feelings sound like"

I profile my bracing pretty much the same for every guitar. Normally, what I alter is the bridge material and the top thickness. I'm very exacting with the profiling of my bracing. I reduce weight as much as possible in most locations but not all. I think the vast majority of builders loose the ability to make informed and educated changes to their bracing because of lack of build consistency from guitar to guitar. Because my work is so incredibly consistent from guitar to guitar - I feel like I can better discern how certain bracing changes affect my sound.

Just my opinion, but I think you'd have to build many thousands of guitars to develop the kind of skill where you could knowledgeably carve and alter a brace in situ and have certainty that what you are doing is actually improving the work (after the guitar has been strung up is a different matter tho'). I think a better route is to thoughtfully develop a bracing design and profile and use that as a future standard - and optimize it based on what you feel is lacking. Necessarily, you'd need to build a few to get an idea of what your "sound" is ... but then make informed and specific changes from there.

If this perspective appeals to you then here are a few things to consider in terms of becoming consistent from guitar to guitar

1) Bridge plate material and thickness -- the cut and strength of the wood needs to be kept the same.
2) Brace wood -- weigh your material and test the strength.
3) Be exacting and consistent with your back bracing too.


After a 4 or 5 guitars, consider what changes you think your instruments could use. More bass, more sustain, more vibrant or responsive -- make informed changes to your bracing or top thickness that may push it in those directions.

after over 20 years of building I pre shape my braces to about 80% then do a final voice after I glue up.
best advice I can give anyone is to keep a building log. There is a balance between structural sound , over built or under braced and learning that is something you have to master .
If your going to sell guitars , understand what the structural integrity of the braces are.

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

I use a .022 CF laminate in my braces. It is hard on tools to carve the CF after gluing to the plate. So I preshape them about 80%, before attaching them. But i only shape the profile. I still use chisels and planes to do the final shaping after the braces are glued on. If I need to change the profile at this stage I hit the brace with a ROS then back to the hand tools.

_________________
Joe Beaver
Maker of Sawdust

Thanks so much for the feedback. I have built around 12 guitars but have been away from building for about 5 years meaning I am re-learning everything over again and making old mistakes all over again as well. I find I am extremely undisciplined when it comes to keeping records and logs and doing anything the same way twice, always seem to be experimenting with something new which adds to the inconsistency.

Pre-shaping braces seems like a natural time saving exercise but without the discipline I'm reading in to all the advice above it's a rather unimportant part of the process. I pre-shaped the last set of 'V' braces I'm experimenting with and found it to be much easier in a couple of regards but am not sure I'm adding any relevant data to my (scattered) process...

Just got a deflection testing setup and perhaps that's a start and will pre-shape my braces but try and keep records of changes etc. which seems to much more important than any time saved pre-shaping...

_________________
Thank You and Best To All

I pre-profile most of my braces. They still get carved after glueing. https://youtu.be/C_5q7PEd-jQ

Are you computer savvy? I created a simple spreadsheet with guitar number, build materials, source of materials, top deflection and final thickness, bridge plate thickness, etc.... It only takes a couple minutes to enter the data especially when it's still fresh in your mind.

If nothing else take pictures.

Cheers, M

It goes without saying that the bottoms need to be profiled first. I have been trying to profile more and more before I glue to try and carve some time off my builds. If you are go-barring them in and the sides are too profiled it is hard to get the Go-Go Bar to stay on. If the tops are too profiled you either need more clamps or use calls to distribute the clamping pressure. Vacuum would be ideal for completely profiled braces.

New username, same Pat Mac

_________________
Pat

Hi Pat,

Here's how I deal with glueing a pre-profiled brace on my go-bar deck. I save all of my brace cut-offs and store them in a tub near my decks for this very purpose.

M

That’s smart, Michael.

I pre-shape with a chamfer bit following the Gore book. I use these little wedges to clamp which tent over top of the brace peak so it doesn’t crush.



Brad


Sent from my iPhone using Tapatalk Pro

_________________
Insta - https://www.instagram.com/cbcguitars/
Facebook - https://www.facebook.com/cbcguitars

Good ideas Michael and Brad! Although it seems like you would need to take them off to clear out the glue and then put them back on. Brad is that a brace indexing pin in the foreground?

New username, same Pat Mac

_________________
Pat

Yes, I have placement pins laid out for the sizes I build:



The jigs I made to put the radius on the bottom and the chamfer on the top have indexing pins as well that are the same distance as the work board.

I use a long piece of thin ebony from a fretboard cutoff to clean up squeeze out so I don’t have to take all the cauls off. If there is a funky place I sometimes have to take one or two up to get it good and clean.

Edit: This is actually a more recent picture. I moved away from wooden dowels and to metal pins.




Sent from my iPhone using Tapatalk Pro

_________________
Insta - https://www.instagram.com/cbcguitars/
Facebook - https://www.facebook.com/cbcguitars

I like your idea Brad. I had thought up a few different ways, but leaving the ends unprofiled and putting a pin and there is a great idea!

New username, same Pat Mac

_________________
Pat

The bottom of the brace gets a radius the full way, but the top stays square. The jig to put the chamfer on the top is marked so I stop just short of the brace end (and just short of the pin).


Radius jig:


Chamfer jig:


Sorry to hijack the thread!


Sent from my iPhone using Tapatalk Pro

_________________
Insta - https://www.instagram.com/cbcguitars/
Facebook - https://www.facebook.com/cbcguitars

Pat,

I actually tip the brace into place so there's only cleanup on one side, the side away from the bridging. I clean up the squeezout and move to the next brace. I tip the next brace into place and bridge from the previous brace, then clean it up. Pretty quick, clean, and easy..

You gonna get a chance to head over here any time soon?

Best, M

I used to pre shape my braces on the router table, and carve the height down as needed, but I found that many times I wanted more mass in the overall picture than the preshaped braces allowed for. So now I profile the sides of the braces with a Boone plane according to the objective of the project.

I "carve" my braces to 95% finished using only the bandsaw and 6 X 89 sander, no jigs-Takes 5 minutes per brace.

I radius the bottoms but otherwise shape them after gluing. Carving braces with a sharp chisel and finger planes is one of my favorite parts of building. I like to think I am voicing every top optimally but quite honestly when I look at my records the measurements are fairly consistent.

I have been at Jim Olson’s shop several times, he has drawers full of pre-shaped braces complete with scallops. That has to tell you something.

_________________
It's not what you don't know that hurts you, it's what you do know that's wrong.

I'm sure it would, but what?

"I'm sure it would, but what?"

That as production goes up things become more standardized. In order to meet demand you either have to create more labor ( work longer or hire people), improve efficiency or cut corners (or all three). When you watch videos of some of the more successful small shops you often see tooling developed to perform a specific task, much as a factory does. With the right quality control having some parts premade to standard dimensions may not be detrimental to the finished product. Perhaps we put too much faith in our chisels and planes and measurements and our ability to "optimize" the materials we build with. We want to believe we are not just "groping in the dark" and that our efforts are better than just building to a plan and letting the chips fall where they may.

Some great ideas here!
I also carve after gluing.
Much like toonces, I am very also very exacting in brace profiling and choice of top materials - after finding the "signature" tone I was after.
Keeping a detailed log as well as taking play-by-play pictures has been very beneficial in consistently replicating the sound I am after, altering only the top thickness per the Gore spectroscopic testing....

I don't disagree with either approach but I think Clay pretty much nailed it; a more standardized process promotes efficiency and that makes it more likely that you can make money, if that is your goal. I think that anyone who has been through the process of trying to make a small custom shop into a money-maker will come to several conclusions driven by simple economics (at least I did when I was building custom furniture). By money-maker I simply mean the shop cannot lose money and has to pay a reasonable hourly wage. This is just what I've found from my experience.

The first thing I figured out is that if you want to make one-of-a-kind custom pieces and make a living wage then you will have to charge a premium price for each piece. That is to cover the low production rate, extra design cost and extra labor required to either do work without jigs/fixtures or build custom jigs for the job. The second thing I figured out is that the market for high $ premium work is limited and it's just not easy to get enough high $ work to support a small shop. I realized if I was going to make money I had to cover time and materials costs and pure custom work, as much I loved doing it, was just not cutting it.

The obvious next step is to reduce the time spent per piece and produce more products at a lower price in order to appeal to a bigger market. That pretty much drives you to standardize what you're doing to some degree by limiting the number of different things you are building, providing a smaller range of options and using as many fixtures/jigs as possible along with common parts and processes. This is what I've seen with many of the small production shops. Doesn't mean you can't offer a high quality product but it does mean you have to focus and not try to do everything just cause you can.

This is why I do setups and repairs to make money. I build guitars for fun.

Just me rambling

_________________
Steve Smith
"Music is what feelings sound like"

Well, that's pretty ingenious about tipping them and only getting squeezz out on one side! I'll have to give that a try.

We are going to be on the canal for the next couple days, and there has been talk of Waterfront . I'll give you a shout if we make it out your way.

New username, same Pat Mac

_________________
Pat