Luthier Glossary of Terms

May 22, 2020

Luthier Glossary of Terms

The luthier profession as in any profession has its' share of unique terms that apply or are are used as standard terminology. The list in this article is intended to give you insight to learn about these terms and exactly what they are and mean, This way you are less likely to misunderstand something that is said on this site.

We will be constantly editing this section as we get questions, so please if you don't fully understand something pleas comment and we will answer and possible add the terminology on this page.

Abalone: This is a type of shell that is used to decorate instrument fretboards, headpieces and backs. Strips of Abalone are used as feature strips around sound-holes, as purflings on tops, backs and sides. Abalone is usually quite colorful ranging from reds to greens and just about every color in-between.

Action: This is a term referring mostly to string height above the frets and fretboard. If a guitar or ukulele has high action it is said to play hard. If a guitar or ukulele has low action it may be prone to string buzzing. High actions is usually caused by improper nut and saddle adjustment.

Adjustable Truss Rod: This is a rod that is placed in a channel of the neck and is just below the fretboard. It has an adjustment nut at either end and allows adjustment of Neck Relief. There are single action rods that only allow neck flexing in one direction and two-way rods that allow you to bow a neck in either direction.

Back Plate

Back Plate: The back wood of the instrument.

Backward Bow: This is a term that refers to Neck Relief. Backward Bow is NOT desired in our guitars. We have to raise the Guitar Action when we have Backward Bow. See Also Forward Bow.

Binding: The binding is the wood (or plastic) trim that joins the top to the sides or the back to the sides and protects the edges of the instrument. The Purfling also serves to prevent excess moisture from entering the end grain of the top and back woods. Note: on many acoustic guitars the binding is made from multilayer plastic.

Book-matched: Book-matched pieces of wood are pieces of wood that are cut out of the same log, cut directly adjacent to each other. When they are then laid open, it looks like a mirror. In the guitar making profession it is very important that top plates, sides and back plates are all glued together in a book-matched fashion. When you buy your wood plates from a luthier supplier, they most likely be book-matched.

Bridge: Bridges come in many different configurations. Classical Guitar Bridges and Ukulele Bridges are vastly different from Acoustical Guitar Bridges. Both are glued to the surface of the top but the Acoustic Guitar Bridges have the strings pass through the Bridge and the Top, where the Classical Guitar and Ukulele strings are tied to the top of the bridge.

Bridge Pins

Bridge Pins: These are small tapered, round wedges that actually wedge the strings to the bridge of an Acoustic Guitar Bridge. They are made from either plastic or Hardwood. There is quite a controversy as to whether wood pins contribute to a good sounding acoustic guitar.

Bridge Plate: Used in all  the acoustic instruments is a reinforcement plate that is glued directly to the underside of the top plate. Materials vary. Classical Guitars and Ukuleles use the same wood as the top. Acoustics Guitars usually use a hardwood of some type.

Butt Block:
The lower block inside the guitar body. This block serves as reinforcement for the side joints and provides a location for the Butt Pin for a strap to be inserted.

Checking: Checking of wood refers to wood that has split, usually due to over dryness or wood that is dried too fast.

Clampling Caul or Just Caul: This is a block of wood to assist in clamping differing parts of the guitar.

Dovetail Neck Joint: This is a form of attachment for Acoustic Guitars. It is a tapered wedge that is designed to pull the neck into the neck slot and tightly fit the neck against the body of the guitar.

Foot: The pertains to the Classical Guitar. The foot is an extended portion of the head block portion of the neck that is located and attached to the back of the guitar. You can see the foot by looking through the soundhole. Many luthiers give the foot credit for additional structural support and tone.

Fret: Small metal bars that divide the neck into half-tones. Frets have a Crown and a Tang. They are usually make from composite metals, which includes about 18% silver.

Fret Crown: The distance that a fret protrudes above the fingerboard.

Fret Tang: The metal tendon that extends into the wood of the fingerboard. Tangs usually have barbs to prevent them from easily pulling out.

Forward Bow: A slight amount of Forward Bow is desired to allow for lower String Action on our guitars. It is a slight cupping or convex shape of the neck.

Grain Silk: Silk results from tonewood that has been cut with nearly vertical grain, which is highly prized. The silk are modular rays running perpendicular to the annual rings and signifies a very stiff top. Many guitar makers feel that a top with silk or modular rays is a better sounding top.

Headblock: A block of wood usually made from mahogany. For an Acoustic Guitar this is the main structural block that serves as the connection point for the neck.

Headstock, Peghead or Headpiece: Used as the attachment point for the tuning machines. Also call the Head of the guitar.

Heel: The heel is the part of the guitar neck that joins the body of the guitar. It us usually the full depth of the guitar. This is an area that many luthiers create their own design as the heel can be made in many different configurations.

Heel Cap: Some Guitars have a heel cap which is a contrasting colored piece of wood that trims off the bottom of the heel were it joins the back of the guitar. Sometimes guitar builders extend the back of the guitar over the heel to form a cap from the back wood.

Lining: The lining is either solid wood, small wooden blocks or segmented tapered or rounded wood that is glued to the inside of the guitar. It is used to join the top to the sides and the back to the sides.

Lower Bout: This is the lower wide part of a guitar, equivalent to the hips of a person.

Luthier: A person involved with the construction of stringed instruments.

Neck Relief: This is a slight curvature along the guitar neck. It is best to have a slight downward curvature so when string vibrate they do not buzz on the adjacent strings. It is mostly concerning with acoustic guitars and is adjusted with the Truss Rod.

Nut or Guitar Nut: This is a small piece of plastic, bone or ivory that exists at the intersection of the Guitar Headpiece and the top end of the neck. This is the beginning of the total string length or scale length of the guitar.

Peghead, Headstock or Headpiece: Used as the attachment point for the tuning machines. Also call the Head of the guitar.

Purfling: The purfling of a guitar is usually a multi-colored thin laminate wood feature that is place between the guitar back or top and the purfling.

Quarter-sawn Wood: This is wood that is cut as closely perpendicular to the grain in the log as possible. It yields grain that is nearly vertical.

Acoustic Guitar Rosette

Rosette: Either plain or fancy decoration around the sound-hole of a Classical or Acoustic Guitar. Classical Guitar Rosettes are usually made from very small repeated mosaic wooden blocks. Guitar rosette vary widely from single accent lines to multi-lined layouts, abalone shell, and decorative inlays.

Relief: The amount of Forward Bow, cupping or convex shape that a guitar neck possesses. Also see Forward Bow and Backward Bow.

Run-out: This is the orientation of the sawn piece in relation to the axis of the tree. If the lumber is not cut parallel to the tree axis, or is the tree grows with a twist, the longitudinal fibers will run off the face of the board. Runout in a top plate is extremely hard to spot.
Wood Grain: Since the trees grows fast during the warm months and slow during the winter months the growth rings are divided into annual rings. This fast growing portion of the right is light and slow growing is dark. Usually the closer the growth rings the better. say 20 to 32 grains/inch.

Bridge Saddles

Saddle or Bridge Saddle: This is opposite end of the nut or the ending of the guitar string length or scale length. The Saddle is constructed from plastic, bone or ivory. The height of the saddle helps determine string Action.

Strings or Guitar Strings: Slang term is also Wires. On an Acoustic Guitar strings are most often made from brass, phosphor bronze or a composite called 80/20's. The plain strings are usually Stainless Steel. Classical Guitar strings are usually wound silver around a fiber core. Plain strings are usually nylon, thus a nylon string guitar.

Tail Block: A block of wood, usually made from Spruce or Mahogany. Its purpose is to provide structural support for the joint of the guitar sides, where they meet at the bottom or butt of the guitar. On an Acoustic Guitar the Tail Block also serves as the connection point for the strap pin to attach guitar straps.

Tie Block: This is the portion of the Classical Guitar Bridge where the strings are looped, twisted and secured to the guitar bridge.

Top Plate: The top wood of the guitar

Tuning Machines: These are the mechanical devices that are responsible for loosening or tightening the strings. They are fastened to the guitar Headpiece. Classical Guitar Tuning Machines are manufactured with 3 per side, all connected together. Acoustic Guitar Tuning Machines are usually manufactured separately or individually.

Waist: This is the thin mid-section of a guitar, equivalent to the waist of a person.

Upper Bout: This is the upper wide part of a guitar, equivalent to the chest or bust of a person.

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