page_title: Tune-o-matic
section_title: Construction
hierarchical_section_title: Tune-o-matic / Construction
caption_attribution_description: Tune-o-matic Classique
context_page_description: Tune-o-matic is the name of a fixed or floating bridge design for electric guitars. It was designed by Ted McCarty and introduced on the Gibson Super 400 guitar in 1953 and the Les Paul Custom the following year. In 1955, it was used on the Gibson Les Paul Gold Top. It was gradually accepted as a standard on almost all Gibson electric guitars, replacing the previous wrap-around bridge design, except on the budget series.
context_section_description: Both the ABR-1 and Nashville Tune-o-Matic bridges consist of one oblong saddle which holds 6 saddle inserts and their corresponding string length (intonation) adjustment screws. Later ABR-1 bridges also have a saddle retainer wire that holds all the saddle inserts and screws in place. Both are mounted to guitars via two threaded posts that may be screwed directly into the guitar's solid body (old style), or into threaded anchors that are pressed into the body. These bridges are also used on some archtop hollowbody guitars, such as the Gibson ES175D, which use a floating rosewood or ebony base (or foot) with two threaded posts screwed directly into it. 
  To adjust the string height (action), the Tune O Matic bridge sits atop two threaded wheels screwed on to its threaded posts. Some have integrated wheel posts that thread into anchors, but they are less common. 
  Each saddle insert has a small groove that matches string gauge and shape to keep the string from slipping off the saddle insert. When fully assembled, each string sits astride a saddle insert and thus "marks" the end of the sting's vibrating length- from the string nut to the saddle insert. 
  After passing over the saddle insert, each string makes a slight downward angle toward the stopbar tailpiece, vibrato, or on hollowbody guitars a trapeze tailpiece. Some solid body guitars have  "strings through the body" construction. Whichever way the strings are held, the fact that the string makes a downward angle after the saddle creates "break angle". Break angle keeps the string from popping out of the saddle insert's groove because the angle causes the string to sit tightly over the saddle. Break angle also contributes to the guitar's sustain and on an acoustic guitar, its volume. There is also break angle created over the nut caused by the headstock pitching back.
  The Tune-o-matic bridge is not absolutely flat, and standard Gibson Tune-o-matic bridges have a 12" radius. Ideally, the radius should match the radius of fretboard for the most comfortable playing experience.
  Due to its symmetrical design, it's possible to accidentally fit the bridge on backwards on the two posts. This can lead to a certain amount of confusion if the bridge is ever removed for any reason. Conventionally, the string length (intonation) adjustment screw heads of the ABR-1 bridge face the neck, and the screw heads of the newer "Nashville" bridge face the stopbar. Unless the player wishes to completely reset the action and intonation, it is important to refit the bridge in the same orientation as before a string change, regardless of which way round it was to start with.
caption: Disassembled Tune-o-matic
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