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Necks

Electric guitar necks vary in composition and shape. The primary metric of guitar necks is the scale length, which is the vibrating length of the strings from nut to bridge. A typical Fender guitar uses a 25.5-inch (65 cm) scale length, while Gibson uses a 24.75-inch (62.9 cm) scale length in their Les Paul. While the scale length of the Les Paul is often described as 24.75 inches, it has varied through the years by as much as a half inch.

Frets are positioned proportionally to scale length—the shorter the scale length, the closer the fret spacing. Opinions vary regarding the effect of scale length on tone and feel. Popular opinion holds that longer scale length contributes to greater amplitude. Reports of playing feel are greatly complicated by the many factors involved in this perception. String gauge and design, neck construction and relief, guitar setup, playing style, and other factors contribute to the subjective impression of playability or feel.

Necks are described as bolt-on, set-in, or neck-through, depending on how they attach to the body. Set-in necks are glued to the body at the factory. This is the traditional type of joint. Leo Fender pioneered bolt-on necks on electric guitars to facilitate easy adjustment and replacement. Neck-through instruments extend the neck to the length of the instrument so that it forms the center of the body. While a set-in neck can be carefully unglued by a skilled luthier, and a bolt-on neck can simply be unscrewed, a neck-through design is difficult or even impossible to repair, depending on the damage. Historically, the bolt-on style has been more popular for ease of installation and adjustment. Since bolt-on necks can be easily removed, there is an after-market in replacement bolt-on necks from companies such as Warmoth and Mighty Mite. Some instruments—notably most Gibson models—continue to use set-in glued necks. Neck-through bodies are somewhat more common in bass guitars.

Materials for necks are selected for dimensional stability and rigidity, and some allege that they influence tone. Hardwoods are preferred, with maple, mahogany, and ash topping the list. The neck and fingerboard can be made from different materials; for example, a guitar may have a maple neck with a rosewood or ebony fingerboard. Today there are expensive and budget guitars exploring other options for fretboard wood for instance Pau-Ferro, both for availability and cheap price while still maintaining quality. In the 1970s, designers began to use exotic human-made materials such as aircraft-grade aluminum, carbon fiber, and ebonol. Makers known for these unusual materials include John Veleno, Travis Bean, Geoff Gould, and Alembic.

Aside from possible engineering advantages, some feel that with the rising cost of rare tonewoods, human-made materials may be economically preferable and more ecologically sensitive. However, wood remains popular in production instruments, though sometimes in conjunction with new materials. Vigier guitars, for example, use a wooden neck reinforced by embedding a light, carbon fiber rod in place of the usual heavier steel bar or adjustable steel truss rod. After-market necks made entirely from carbon fiber fit existing bolt-on instruments. Few, if any, extensive formal investigations have been widely published that confirm or refute claims over the effects of different woods or materials on the electric guitar sound.

Several neck shapes appear on guitars, including shapes known as C necks, U necks, and V necks. These refer to the cross-sectional shape of the neck (especially near the nut). Several sizes of fret wire are available, with traditional players often preferring thin frets, and metal shredders liking thick frets. Thin frets are considered better for playing chords, while thick frets allow lead guitarists to bend notes with less effort.

An electric guitar with a folding neck called the "Foldaxe" was designed and built for Chet Atkins by Roger C. Field. Steinberger guitars developed a line of exotic, carbon fiber instruments without headstocks, with tuning done on the bridge instead.

Fingerboards vary as much as necks. The fingerboard surface usually has a cross-sectional radius that is optimized to accommodate finger movement for different playing techniques. Fingerboard radius typically ranges from nearly flat (a very large radius) to radically arched (a small radius). The vintage Fender Telecaster, for example, has a typical small radius of approximately 7.25 inches (18.4 cm). Some manufacturers have experimented with fret profile and material, fret layout, number of frets, and modifications of the fingerboard surface for various reasons. Some innovations were intended to improve playability by ergonomic means, such as Warmoth Guitars' compound radius fingerboard. Scalloped fingerboards added enhanced microtonality during fast legato runs. Fanned frets intend to provide each string with an optimal playing tension and enhanced musicality. Some guitars have no frets, while others, like the Gittler guitar, have no neck in the traditional sense.