Once upon a time, crafting the body of a guitar took a lot of hand tools, artisanal skill and time. But today, most mass manufactured guitars are made with a variety of templates and heavy machinery that allow workers to quickly cut and piece together quality guitars. Thanks to innovations in the process, acoustic guitars are much cheaper than they once were.
Want to know exactly how these guitars are so efficiently made? Read on.
Acoustic guitars — good acoustic guitars — are made from spruce or cedar trees that are roughly 800 years old or more. At this stage, these trees produce wood with many of the qualities need for a great guitar: strength to stand up to the constant tension of the pull of the strings, flexibility to absorb and reflect the vibration of the music created with those strings and relatively light weight to make the acoustic guitar portable and easy to carry.
Thin sheets of the cedar or spruce trees are laid out on a table. Then a guitar body template is placed on the center of the sheet. A 30 ton press presses down on the guitar template and it cuts the back face of the body out of the wood like a cookie cutter cuts cookies out of dough. A second sheet is used for the front face of the body.
The sound hole is cut out of the front face of the body of the guitar using a large carefully calibrated drill and specially designed hole saw. The size of the sound hole is precisely controlled. The larger the sound hole on the guitar, the more treble the acoustic guitar produces. A smaller hole produces a sound that has more bass.
A specialized drill then cuts a shallow groove around the sound hole. A decorative circle of wood, called a rosette, goes in the groove to give the guitar character and personality.
The sides of a guitar are made of two thin strips — the left side and right side — of cedar or spruce wood. Before they can be shaped into the delicate curves of a guitar’s sides, they must first be submerged in boiling water for a few seconds.
Once the pieces are supple, they go into a heated metal press that is shaped like the curves of a guitars sides. After a minute or so in the press, the guitar sides are just the right shape. Then technicians take them out of the press and clamp the right and left sides of the guitar together and join them by gluing them to small blocks of mahogany or poplar wood at their top and bottom joints.
The bottom joint is glued to the block of wood while it is in the clamp. The top
They are removed and affixed to either side of the front and back of the guitar’s body with clamps and wood glue.
A wooden lining is then glued and clamped on to the inner lip of the connected guitar sides. A hand router creates small notches on parallel points around the wooden lining’s protruding lip. Three parallel wooden braces are inserted and glued into the lining to create a brace for the back face of the guitar to rest on.
The front face of the car requires a more complex series of criss-crossing braces that are glued and vacuum pressed directly onto its back. These braces will help the guitar withstand the tension of the strings once construction is complete. Their unique positioning also helps to control sound quality by creating different vibrational frequencies at different areas along the face of the guitar.
Once all of the braces are vacuum pressed into place, the front and back faces of the guitar are glued and clamped on to the small blocks of mahogony or poplar used to join the guitar sides together. The completed body is pressed for several hours to allow the wood glue to dry securely.
Finally, a plastic binding is glued all around the guitar’s exposed edges to keep them from separation and exposure to the elements. A quick sanding with a power sander and four to eight coats of lacquer finish the body’s basic construction.
Holes for the neck are drilled into the top of the guitar’s body using a drill with specialized sensors calibrated to find the optimal placement and angle of guitar neck to guitar body. This angle is very important. It controls the quality of the sound that will eventually come out of the finished guitar.
The neck and head of the guitar is hand or machine carved out of the same type of wood that makes up the body of the guitar. Holes are machine drilled into the head for the machine heads and a large groove is cut down the center of the neck. An adjustable metal rod is placed inside and glued into this groove. This rod helps the neck adjust to the tension of the strings.
The fingerboard of the neck of the guitar is machine cut out of rosewood or ebony wood. Metal frets are then pressed and secured into the fingerboard to represent the half notes of the musical scale. The fingerboard is then glued and vacuum pressed onto the neck of the guitar.
Next, the machine heads are inserted into place. The metal rod in the neck slides into a groove cut into the body of the guitar and the two are clamped together until the adhesive used to join them dries.
Finally the bridge and headstock nut, saddle and bridge pins. The very last step is to string the guitar with an electric winder. Once the guitar is assembled, it’s sound will get better with age as the wood becomes more flexible.