Fret Caul Alignment & Even Pressure
- Aug 8, 2025
- 2 min read
Updated: Jan 31
KINEMATIC DESIGN
Our luthier tool designs are grounded in the principles of kinematics & mechanics. An example of this application is our fret pressing range:-
BASIC PRESS METHODOLOGY
1) Pre-Bent Fret :- Tang constrained within the radiused fretboard slot.
2) Guided Caul :- Constrained within parallel forks.
3) Radius Caul :- Centralises over the fret length for even pressure distribution.
TYPE OF CAUL
Choice of caul depends on individual preference although it is worth noting that a simple radiused caul allows for a small amount of misalignment whereas a grooved caul requires more precise alignment. To achieve the high quality and precision necessary, our grooved cauls are machined in house ensuring the radius is accurate and the groove is uniform along its length.
Q. Will the caul bend a straight fret into the right radius?.
A. The caul wont bend the fret into the desired radius. A Fret bending tool or manual method should be used to pre-bend the frets to the radius required before installation to avoid any spring back from the fret ends.
Q. Should the fret caul be the full length of the fret?.
A. This is preferable as it will ensure uniform pressing over the fret crown for even seating and avoid potential damage. A full-length caul allows the pressure to be distributed evenly across the fret crown, resulting in consistent fret installation along the neck.
Q. Can a caul tip a fret over?.
A. If the caul and fret are not in line or if the caul is extended beyond its limit on the screw, the caul can potentially tip the fret over. For optimum performance and stability a maximum of 10mm-15mm caul travel from the highest position is recommended. This will ensure that the caul is guided correctly in the forks as demonstrated below.
