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Not being an arc top builder I am speaking out side my knowledge base but would assume that flat sawn would dampen the transfer of energy

Chris......I think, if I understand what you mean, I agree with Michael. In both cases, quartering means the little "beams" (grain lines) run vertically. In an archtop, you're just carving a bunch of curved beams. The shape actually makes them a stronger beam.

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Dave
Milton, ON

Bob Benedetto used dimensional lumber for a guitar once. But he's a true master and only did it once.

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Joe Breault
Merrimack, NH
Perpetual novice

I'm not sure that I under stand the term "dimensioned" but I'm guessing that it is what is commonly called flatsawn. The quartersawn wood coming from a "wedge" usually has a better strength to weight ratio than flatsawn whether used in a "flat top" or arch top.

What I will say is that gluing up wedges is Not Fun. Need to take apart the spruce set I glued up last weekend, because the joint is not up to scratch. The jointing was, but the clamping, well, wasn't. Pesky wedges.

The appearance of the bookmatch is an issue that is different between archtops and "flat tops". Whether an archtop plate comes from a wedge or dimensional may have some effect on bookmatch. Having said that, the bookmatch on an arched plate doesn't really "match" along the full length of the center join seam.

Just musing here... It seems to me that runout is not being created by carving quartered wood, any more than a simple crosscut would. Runout is skewed grain that terminates on either a face or a side of a board before it could reach both ends of the board. If you carve a no-runout, quartered board, keeping the grain vertical, you're simply creating quartered grain of multiple lengths. The grain is not skewing in this case. It remains straight and quartered. Comments?

Hey Chris

The archtop sets I produce are all rectangular (about 1.125 x 9.25 x 23 each half for guitars) Both in guitars and Mandolins. My customers prefer this, including Roger Siminoff for mandos and Peter Hopkins for guitars. One thing to remember is that lack of runout makes the top structurally superior which in turn allows you to thin it more, based on the wood properties. This means that a given piece of wood cut well will allow you to build more responsiveness into the instrument than from the same piece of wood cut poorly. I don't do wedges initially because I wasn't set up to do it and then I had this thought that I would like to the wood dry uniformlyand then, my customers just wanted to get their wood in the rectangular form.

Hope this helps!
Shane

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Canada

I think Chris is mainly asking about runnout in the face of the boards. Extream example would be what you see in a curly top as the curls in wavess and does not run parallel to the face of the board.

If you had a perfect board with grain running perfectly straight and parallel to the face and sides. Then you carve an arch into this board. You wind up with runnout on the carved face. This would be un avoidable unless the grain was oriented in such a way that it formed the same pattern as your carved arch(not going to happen).



Peace,Rich

Back to Chris's original post on this topic, doesn't look to me like it makes a whole lot of difference whether wedge or dimensional for an archtop.
Probably should leave this to the more knowledgeable, however, since trees are way over my head.

Chris, I always use dimensional (rectangular) lumber for my archtops. From Shane. Like you, I find it much easier to join a rectangular piece than a wedge.
As far as runnout is concerned: though not truely runnout, the face runnout is inherant to an archtop plate. Unless the tree grew in the shape of an archtop plate, you are going to get this longer grained face runnout on the more vertical cuts of the plate.

With regard to bookmatching, it sometimes works better to put the bookmatch to the inside of the plate. Then the ends of the plate will come close to matching while the peak of the arch is left to chance. Name your poison, I guess.

I don't mean to mix the waters here, but wedge-split, vs. dimensional cut
wood could make a difference because the grain of the wood could
be parallel to the rims or not.

You will get run-out patterns in an archtop, yes (Carlton, I always took
"run out" to be separate from "skewing grain" in that run out is just where
the end grain meets a surface of the wood). But the run-out makes
patterns on the top (especially if you stain it) where the end-grain soaks
in more and face grain soaks in less and overall it gets splotchy.
Depending on how you have oriented your bookmatch, this will either
form a checkerboard effect or a light-dark mismatch to the front vs.
toward the back.

There is the issue with wedge-split or dimensionally sawn wood. With
wedge split, you know that the grain will be parallel to the rims, making
the high point of the arch the only spot where you see the face grain
directly.

However, if the grain has run-out in the dimensional rectangle, that run-
out will put your face grain surface somewhere infront or behind
the top of the arch, which could look silly, or perhaps it is a look you like.

Check these out: First, the wedge situation where the grain is parallel to
the rims (horizontal on the picture)
">

Second, where there is run-out in the flat board, resulting in a different
run-out orientation of the arch.
out.jpg">

I imagine parallel grain is the best structurally, but I'll leave that up to the
experts.

Not sure what happened to the pictures there, I'll try again later.

I'm confused why wedge split would have a different orientation than vertical grained dimensional (rectangular) wood. In both cased the grain is parallel to the sides.
Please clarify.

One more try with the pictures. I should clarify that the lines on the pictures
represent the direction of wood growth NOT the grain lines.

Here is where the orientation is parallel to the rims.
[IMG] ../forum/useruploads/gburghardt/2007-05-02_163539_parallel.g if[/
IMG]

here is the orientation "run out" from the rims.
[IMG] ../forum/useruploads/gburghardt/2007-05-02_163631_run_out.gi f[/
IMG]

Dang... I'll try again later, when I've got more time..

Wedge cut wood:


Dimensional:


Once carved I see very little difference between the two cuts if well quartered.

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Michael Lloyd

“I was born to ignorance, yes, and lesser poverties ...
I was born to privilege that I did not see ... I didn’t know it, but my way was paved” – John Gorka

"The archtop sets I produce are all rectangular (about 1.125 x 9.25 x 23
each half for guitars) Both in guitars and Mandolins. One thing to
remember
is that lack of runout makes the top structurally superior which in turn
allows you to thin it more, based on the wood properties."

Well, the decision to produce lumber (uniform thickness) as opposed to
wedges has nothing to do with avoiding runout....

The decision to cut wedges is all about staying on quarter in a
smaller (30-36" diameter) log....

"My customers prefer this..."

Customers who prefer lumber to wedges are usually working with CNCs
or pantographs, and have to go through another step of glueing on
supports in order to first carve the inside arch of their tops when working
with wedges, which can be a hassle....

If a maker is carving by hand, they obviously prefer to work with wedges,
as it cuts the carving down considerably....

When milling billets split from large Sitka or cedars (5'+ in diameter), one
can resaw archtops in lumber form all
day long from the same billets and stay on quarter....

But if you're working on a "small" (32" diameter) Red Spruce or European
spruce, you kinda have to cut wedges in order to stay on quarter....

In the end, the guitar doesn't know if it was built from lumber or wedges
if both are properly cut...

Oh yeah, back to the original question....

"However, for an archtop, wouldn't that essentially not matter because
by
carving the arch in the first place we're cutting of grain lines and what
not,
in the end doing the same effect as having run-out?"

Yes....

Which is why--in the past 10 years or so--there has been a small
movement
in the violin world to bend plates milled from perfectly split wood
rather than carve them...

There are those who also believe that folks like Strad, Amati, etc. bent
their plates instead of carving them...

I doubt it though, as bent plates are fairly distinctive under varnish with
that bent-plate look...

I probably should have my hands slapped for mentioning book match again since that is not the original topic but oh well. One advantage of bent or laminated plates is a nearly perfect bookmatch compared to carved plates.
Might mention that I prefer wedges (wedgies?)for CNC carving archtop plates. Glueup doesn't present a problem as I flatten only the "inside" surface of the plates and then joint them with an edge sander. Clamp the wedges down lightly with clamps before applying pressure with the main clamps for the glue joint. This keeps the plates down fairly flat even though the main clamps are against the narrow wedge edge. (wedgy-edgy?) I CNC the exterior of the plate first so the wedge again results in less material removal saving wear and tear on the router motor especially in hard maple.
When making the plates from dimensional stock, I sometimes rough carve excess material by hand with a lancelot type tool in the angle grinder before going to the CNC.    Lots of ways to skin the proverbial cat, I guess.
Nelson