Nut Slotting — Lutherie Encyclopedia

Nut SlottingType: techniqueCutting precisely sized and spaced slots in the nut to control string spacing, height, and action at the first fret.## Overview The nut is the slotted piece at the headstock end of the fretboard that guides the strings and establishes their height and spacing at the first fret. Proper nut slotting is critical for comfortable playability, accurate intonation, and buzz-free performance in the open and lower fret positions. A poorly cut nut is one of the most common causes of poor playability on otherwise well-made instruments. ## Process Nuts are made from bone, Tusq (synthetic bone), brass, graphite, or various plastics. Bone is the traditional choice for acoustic guitars and produces a bright, clear tone. The nut blank is first shaped to fit the nut slot in the fretboard—it should seat firmly without forcing and match the fretboard radius. String spacing is laid out by marking the positions of each string on the nut. The outside strings are typically set 1/8 inch (3mm) from the edge of the fretboard, with the remaining strings spaced evenly between them. Some luthiers use slightly wider spacing on the bass side to account for the thicker strings. Slots are cut using specialized nut slotting files—thin, round-section files matched to specific string gauges. Each slot is filed to the exact width of the string it will hold: too tight and the string binds, causing tuning problems; too wide and the string rattles or shifts. The slot depth determines the string height at the first fret. As a starting point, the bottom of each slot should place the string approximately 0.020 inches (0.5mm) above…