Fret Rocker — Lutherie Encyclopedia

Fret RockerType: toolA short, precision-ground straightedge that spans three frets to detect high frets causing buzz.## Description A fret rocker is a short, precision-ground straightedge, typically 70mm to 100mm long, used to check whether individual frets are higher than their neighbors. When placed across three adjacent frets, it should sit flat. If it rocks on the center fret, that fret is high. Many fret rockers are multi-edged, with different lengths on each edge to accommodate different fret spacings along the neck (wider spacing near the nut, narrower spacing near the body). ## Use in Lutherie Fret buzz is often caused by a single high fret that interferes with string vibration. The fret rocker identifies these high frets quickly and precisely. After fretting a new neck, the luthier checks every fret with the rocker to find any that need leveling. It is also used during setup and repair work to diagnose buzz problems. Checking is done on both the treble and bass sides of the fretboard, as a fret can be high on one side but not the other. ## Selection Guide Fret rockers are inexpensive, typically 5 to 20 dollars. The Stew-Mac precision fret rocker is a popular choice with four different edge lengths. Hosco and generic versions work equally well. The critical quality is that each edge must be perfectly straight. Verify this by holding the rocker against a known-flat surface and checking for light gaps. Some luthiers use a small machinist straightedge as an alternative. ## Tips - Check all frets systematically, moving up the neck one fret at a time, on both treble and bass sides. - A…