An interesting nugget of information from fabled luthier Ken Parker on wood cuts for necks.

"First of all, the term "quarter sawn" is antiquated. No one saws wood like this anymore, with only one exception, and that is for the purpose of rendering thin sheets of spruce or cedar for the purposes of making acoustic guitar tops. In this case, short billets of very special spruce are radially split with wedges, and then a bandsaw is used to slice thin sheets from the split face.

As someone in the forum correctly points out (along with an excellent illustration), in old-fashioned quarter sawing, boards are sliced alternately from the two straight faces of a quartered log. The only other exception is oak, which is commercially available all three grain orientations, as the look of the board's surface is very different in the 3 styles of lumber due to the gigantic medulary rays in oaks.

There are three styles of lumber.

1) The most common is known as flat sawn, or plain sawn material. This means that the faces of the board are parallel to the tangent of the outside of the tree. This is how you cut lumber in order to maximize yield. When you look at the face of a flat sawn board, you might see undulating lines, sometimes ovals, V, or W shaped grain patterns. Looking at the end grain, you see long arcs of growth lines. There is nothing wrong with flat sawn wood for most purposes. For example, nearly all the Fly guitars were made of flatsawn material with the exception of the softwood guitars made with Spruce or Cedar bodies, which were all vertical grain material. Flat sawn wood has good stiffness, and is mostly a stable configuration, but it does have a tendency to curl, or "cup" with changes in moisture content. When it does "cup" it curls in the opposite direction of the grain lines. In other words, it would cup towards the outside of the tree.

2) Vertical grain material means that the grain lines are perpendicular to the face of the board. When people say, "quarter sawn" they almost certainly mean vertical grain. Vertical grain material has the best stiffness both along and across the grain. it is the only choice for soundboards, whether it is guitar, violin family, piano, harpsichord, etc.

The big advantages of using vertical grain material, aside from its very regular straight grained appearance, are two..........

First, because wood shrinks, mostly in the direction of the grain lines, a vertical grain piece of material will shrink much less across its width than the other two grain orientations. This is important not only to instrument makers, but to furniture makers, and for any wooden product that is precisely made and will be exposed to changing conditions of humidity.

Second, in many species of wood, there are fibers that emanate from the center of the tree, growing horizontally and extending through the wood, weaving between the vertical grain lines. These fibers are called medulary rays, or cross grained fibers, and can materially contribute to the cross-grain stiffness of vertical grain material in which they occur. Because these cross grain fibers constitute a small proportion of the wood, and because they only occur as radii, they do not greatly effect the properties of flat sawn material.

3) if a piece of material falls between 1 and 2, it is said to be rift sawn, or slash grain. Structurally, this is the least wonderful material, as when stressed it tends to bend off to one side. For this reason, avoid a Fender style neck with rift grain. Although vertical grain would be best for a neck, flat sawn material is a close second.

When you look at the end of a rift cut board, the grain lines form an angle with the face. If you look at the quartersawn drawing on the forum, you'll see that most of the material produced by old-fashioned quartersawing is actually rift cut. This is responsible for much of the confusion, as "quartersawn" lumber can be both vertical and rift.

It is worth knowing that the structural benefits contributed by the cross grained fibers in vertical grain material are dramatically reduced by the grain being even 5∞ off vertical. So, when seeking ultimate structural properties, ( like I am, in thin material for acoustic guitar making), material that is not perfectly vertical grain can be considered rift material: that is, less stiff across the grain.

One more thing,..... the material that we used to make the tulip guitars is exactly the same kind of material that was used in the deluxe. That is, it is all tulip poplar, or yellow poplar. The boards that we used for those special guitars were ones that I culled out over a period of years for evenness of color and appearance. Almost all the poplar that we were able to buy was green in the middle ( heartwood ) and a kind of dirty off-white color on the edges ( sapwood ) . No one considers this attractive, so all the deluxe guitars made of Poplar had solid finishes. The poplar boards that I was able to set aside for this small run were very special and unusual boards."