Selecting the wood for guitar
When lumber is cut from logs, it is typically cut in one of three ways: quarter sawn, rift sawn or plain sawn. Each type of lumber is dependent on how the log is oriented and cut at the sawmill. The result is a particular orientation of the growth rings on the end grain of the board and is what defines the type of lumber. The type of cut also determines the figure in a piece of wood and the wood’s mechanical properties.
PLAIN SAWN / FLAT SAWN
Plain sawn, also commonly called flat sawn, is the most common lumber you will find. This is the most inexpensive way to manufacture logs into lumber. Plain sawn lumber is the most common type of cut. This look is the result of the annular rings being 45 degrees or less to the face of the board (known as tangential grain). Flat sawn lumber is the most inexpensive option because it is the easiest to obtain. Generally 60-70% of the lumber from a log is flat sawn. The rest is quarter sawn or somewhere in between.
Quarter sawn is a lumber that went though the following cutting process: The log first cut axially into quarters; then, for each quarter section, a slice is taken from one of the flat sides, then the quarter is rotated and a slice is taken from the other flat side. This process is repeated until the quarter section is all sawn into boards.
Rift sawn lumber is typically narrow with a very straight grain pattern on the face of the board. ... The annular rings or a rift sawn board are about 30-60 degrees to the face of the board, but 45 degrees is the most optimum. Similar to quarter sawn lumber, rift sawn lumber is also referred to as radial grain. Rift-sawn wood is the one you see on violin's top: the fibers run long and strong, with the straight year lines clearly visible, providing more resistance and flexibility than any other cuts.
Similar to Basswood, alder is lightweight with soft tight pores. It also has a large swirling grain pattern to it. These larger rings and sections add to its strength, and the complexity of the tones.It’s relatively form stable during moisture variations. The Alders color and structure of the wood, softness and reluctance to shrinkage and swelling makes it suitable building guitars. Alder is perfect for bodies. Mids are pronounced but it still has a nice rounded bottom and and bright top end.
Hardness: Janka: 440 at 12% moisture
Brinell: 3.7 at 12% moisture
Density: 470-510 kg/m3 at 0% moisture ratio (u)
500-540 kg/m3 at 15% moisture ratio (u)
Mahogany is a porous, but strong wood which is easy to machine and finish. It has a spiraling and interlocking grain pattern which makes it a very stable wood. Honduran Mahogany is the favorite choice of instrument builders, but is very hard to find. Mahogany ranging in color from light brown to dark. It has a balanced, resonant tone with notable sustain. Mahogany delivers a thick bottom end, rich midrange, and controlled, warm top end.
Hardness: 4751 N at 12% moisture (1070 lbf.)
Stable and strong, Maple has a brightness to the top end and tends to tighten the bottom end when combined with warmer timbers. Very popular for necks, and tops. Birdseye maple is recognizable by conical indentations that grow out of the growth rings of the tree, usually with a diameter of 1/16” to 3/8”. In Birdseye maple lumber, the sap wood of the tree is usually creamy or light amber in color with a medium to hard density. The heartwood is usually reddish or darker brown.
Hardness: 1,450 lbf (6,450 N)
Macassar and Gaboon Ebony
Size limitations of available stock prevent it from being widely used for the guitar body itself, but there are some out there. An Ebony fretboard feels silky smooth due to it's tight grain structure and lack of pores. Tonally it is the brightest of timbers. Similar to African Ebony in tone, although not quite as bright. Very close pore structure leaves a nice smooth feel for fretboards.
Hardness: 3,220 lbf (14,140 N)
Ebony, one the heaviest of the hardwoods, is very dense, machines well, and resists warping. Ebony is a popular wood for fingerboards due to its stability and strength. It holds frets extremely well and has a striking appearance. It will also add great strength & stability to your neck.
Koa is lightweight and has a wonderfully compressed dynamic range. It combines clarity with warm, thick tone and produces incredible separation for individual notes.Koa wood is diverse and complex with an incomparable appearance.
Hardness: 5195N at 12% moiture (1170 lbf.)
No two pieces are alike with Buckeye Burl. From intense swirls and wild grain, to colours ranging from beige, through grey/blues, to near black, it is one of the most interesting timbers to look at. Because the grain is twisted and interlocked, burl wood is extremely dense and resistant to splitting.
Extremely light bodies have a weak bottom end and sound thin. Popular in the 50's for electric guitars this wood is alive and light weight. Swamp ash just wants to vibrate. Bright and sweet at the same time, excellent grain pattern, all transparent finishes look great on Swamp Ash.
Hardness: 590 lbf (2,620 N)
Purple heart behaves like Maple & Ebony. It makes excellent fingerboard wood. Usually it is used for accenting other beautiful woods. In short, although it is a wood a little bit complicated to work with, if you chose Purple Heart sides for your Classic Guitar, you instrument will have a different and unique touch. The colour changes from a bright purple to a dark purple/brown colour as it oxidises.
Density: 880 kg/m3
Hardness: 8258 at 12% moisture