Side Bracing

[Bob Menzel]

I'm going to add side braces to my current project, an OO size which will have laminated Basswood linings. The plan is to use a single thickness of the same Basswood used for the lining for the side braces (or maybe Walnut scrap from the top/sides). Kinkead (et al) simply butts the side brace in between the top and bottom linings. I don't see how that would prevent a crack at this joint and I'm thinking of recessing the side braces into pockets about 1/8" deep. Any caveats you can offer would be appreciated.

[Steve Senseney]

I always use side braces.

They don't have to be very big (width or height). I have used spruce, walnut, maple and what ever I have handy that I want for color or appearance.

I cut the little strips, and take them to the sander and taper them to nothing. I get them about the right length, and trim them exactly with a scissors, as the ends are so thin.

If you leave them full depth to the linings, I worry that it will create a line of stress at the edge of the binding, and increase the risk for a fracture along this area.

[Chuck Tweedy]

I agree - you need to either inlet them into the linings or run the linings over them, otherwise you create a "stress riser" at the butt-joint between the brace and the liner.
I use cloth bias-tape saturated in hide glue. I put these on before the linings, and leave them about 1/4" short of the edge of the rib. Then the linings go right over the cloth.
The cloth strips are to stop cracks, not to add any rigidity like a brace would.
They do have the advantage that they will not constrain the side's movement due to changes in RH.

[Bob Menzel]

So tucking the braces (as I plan) would avoid a stress riser, which is good, but wooden braces don't allow the sides to react to changes in RH, which is not good. Perhaps this would be a good place to take advantage cold creep in an adhesive other than HHG that would allow some movement?

I hadn't planned on bias tape for this project, but if the point of side braces or tape is to simply stop/control cracks I've been pondering the merit of using paper thin shavings (from planing) as an alternate. Has anyone tried or heard of this?

[Randy Roberts]

Bob,
If you are doing a solid laminated lining, then just use some of your lining material for the side braces as well, running the braces the full width of the side.
Glue the side braces first. Then fill in between them with your first layer of linings, which are easily cut to fit between the braces just by holding them butted up to the first brace and then mark the 2nd brace and cut.. Your subsequent lining layers go over top this first layer and lock in the side braces automatically.

Maybe a picture would be clearer..

[Bob Menzel]

Thanks. I know mine won't come out nearly as artistically as yours Randy, but that does seem a whole lot easier than tucking. It will also help solve the problem of having cut one of the liners 1/32" too short.

[Chuck Tweedy]

Your work is exquisite Randy. That is a truly beautiful guitar interior!
And your side braces are perfect = no stress risers there at all - it is all woven together.

[Matthew Lau]

Beautiful work.

[Danny Seamon]

What would that look like in a steel string with kerfing? I'm trying to visualize how to cut a recess into the kerfing.

[Mario Proulx]

Kerfing?

No such animal.....

[Danny Seamon]

Hmmmm... Kinkead calls it kerfing. Cumpiano calls it kerfed linings. What is the proper term?

[Bill Raymond]

Some folks just get a bit cranky about the use of the term "kerfing" to describe what they prefer to call "kerfed lining". You may feel free to just smile and ignore them. We all know what you're talking about.

[Randy Roberts]

Danny,

Cumpiano is correct. Kinkead is using poor grammar, and I believe the Grande Conclave of Master Luthiers revoked his license to speak to the rest of Luthierdom for 5 years because of this grossly negligent slip.

"Kerfed" refers to a lining that has had the slits cut in it. The comment Mario made was a tongue in cheek reference to a long running "discussion" years ago on this forum on proper terminology, that centered around this term. At the risk of igniting that discussion again, I believe the gist of the arguement was this:

When you have slits cut into the lining, it is a kerfed (adjective) lining. The slit is a kerf (noun) that exists solely because of it's surrounding wood, not as an object itself.(I am lighting the match now...) Because the "kerf" is an empty space of just air, "kerfing" would just be a bunch of empty space of air and so does not exist as an entity, and therefore there is no such thing as "kerfing" as a noun. Now, if you are in the act of cutting these slits, then you are indeed "kerfing" (verb). The wood that used to be where the "kerf" now is, that was turned into the dust in the air being breathed into your lungs was the "swarth".

Splitting hairs, maybe, but wars have been fought over this. (because sometimes wars just need to be fought<g>). Elvis has now left the building, and you might want to buy a copy of my latest reference book [Roberts' Rules of Order] if you choose to continue this discussion.


If you want to apply this locking the the side braces in with a kerfed lining, then probably the easiest approach would be to mark the lining where it hits the braces and then it would be short work to just file out a "kerf" for the braces, to the depth of the braces.

[Danny Seamon]

Randy,
As always on this forum, thanks for the education. I didn't know what I had stepped into. Anyway, I follow you completely through "mark the lining where it hits the braces".. can you elaborate on "file out a kerf to the depth of the braces"? Since the kerfed lining is already glued to the sides I wouldn't know how to file out a space for the brace....maybe chisel? (Sorry...my Mom always said that she had to draw me a picture for me to understand.) Also, what is the recommendation about side braces? Do most people use them? I did on the two guitars I've built so far but I just butted them up against the kerfed lining. I'm working on number three now, I'm enjoying the challenges and want to follow what is best.

[Chuck Tweedy]

I didn't know what I had stepped into.

Yep. You didn't.

Now - kerfling, that is an entirely 'nuther beast.

Back to the subject:
Since the linings are already in there, then you need to mark the locations of the inlet braces, and cut out the liner material with a sharp chisel (SHARP!)
And try not to dig up the sides too much.

[Randy Roberts]

Danny,
Oh man, I thought you were still sitting with the linings and braces on the workbench. You're past where what I was talking about could be done. I was working from the braces being on and the lining's yet to be glued on. I was going to have you filing a trough on the glue face of the lining to make a space for your brace.
Chuck's got the ticket I think. just notch a small cavity with a chisel along the bottom of the linings (the thinnest edge) for the brace to set into. Or you could still do Chuck's first suggestion of the glue impregnated fabric and have it just continue on up over the lining when it reachs the lining.

Don't worry about what's the best way, there's always going to be a best way for doing any step, the problem is, it will be a different "best" from each person you talk to.

[Steve Senseney]

Randy is right. A lot of guitars are made without the braces, but I think they are a good idea.

More than one way to do all of this.

[Mario Proulx]

A lot of guitars are made without the braces

99% of those are made of plywood, and thereby are not prone to splitting. All solid wood sides should have some form of braces, whether cloth or wood is up to the luthier.

[Mark Tierney]

Because glued cloth seems to me fairly insubstantial for a brace--more like wishful thinking, maybe?--I always use wood. I tuck the ends of these braces, which come to a broad point, into triangular pockets in the linings: easier to cut and fit than rectangular mortises, yet prevent stress concentration at the meeting of brace and lining equally well. I don't worry about the crossgrained gluejoint on the side, since the risk is less than what is routinely run in traditionally bracing a back of the same wood.

[Mark Swanson]

The main function of a side brace is to stop cracks that run along the grain of the side, and the cloth strips do a fine job of that.