Bridge String Spacing Generator

What this tool is for

Plan saddle centers and string-edge gaps within a measured bridge footprint. Geometry tools apply explicit models to named measurements. A coordinate or angle must still be checked against a physical drawing, real hardware, tolerances, and material behavior.

Use it when you can describe the current state and need a defensible next check. It is not a shortcut around inspection: preserve the starting state, change one variable, and verify the result under the same conditions.

Before you begin

Measure the bridge footprint, desired outer-string center spread, saddle width, real gauges, and bridge type. Identify mechanical saddle limits before selecting a spacing method.

• Use a stable, tuned instrument unless the page specifically investigates tuning.
• Name the physical reference, unit, and test condition beside every important number.
• Keep the original measurements so any reversible change can be returned to baseline.

Input guide

Number of strings

provides a measured or counted input; confirm the allowed range and repeat the reading before relying on it.

Bridge footprint width

supplies a measured geometric quantity whose datum and resolution should be written down.

Outer-string center spread

supplies a measured geometric quantity whose datum and resolution should be written down.

String diameters, comma separated

records the actual string dimensions or supported set rather than a visual estimate.

Spacing method

classifies an observed condition; choose “unknown” or “not tested” instead of guessing when available.

Individual saddle width

supplies a measured geometric quantity whose datum and resolution should be written down.

Bridge type

classifies an observed condition; choose “unknown” or “not tested” instead of guessing when available.

Input and display unit

sets the interpretation and display unit; do not mix units elsewhere in the same run.

Measured 50mm calibration bar (mm)

provides a measured or counted input; confirm the allowed range and repeat the reading before relying on it.

Allowed calibration error (mm)

provides a measured or counted input; confirm the allowed range and repeat the reading before relying on it.

Input labels describe evidence, not targets. A placeholder demonstrates format only; it is never a recommendation for a particular guitar.

How the result should be read

Check every calculated center against saddle slots, pickup pole coverage, neck taper, and outer-fret clearance. The result is a layout comparison, not a drilling template.

Read priorities from top to bottom, but stop as soon as new evidence contradicts an earlier assumption. Save or print the result ticket with the entered conditions so another person can reproduce the decision.

Method and logic

The tool calculates center coordinates and neighboring edge gaps within the entered spread. Equal-gap adjusts center distances for mixed diameters; it does not move hardware beyond its range.

The page keeps calculation and diagnostic claims deliberately bounded. Display rounding improves readability, while the underlying logic uses entered values; descriptive branches report relative tendencies and the evidence needed to confirm them.

Worked example

With a 52 mm outer-center spread across six strings, equal-center intervals are 10.4 mm. Mixed gauges make their physical edge gaps unequal; equal-gap redistributes those center intervals.

The example demonstrates reasoning, not a universal setup specification. Substitute real measurements and repeat the final test before accepting the next action.

Assumptions and limitations

Bridge castings, slotted saddles, string angle, tremolo plates, and manufacturer dimensions constrain placement. Do not drill or file until a full physical mock-up clears all systems.

Instrument design, service history, measurement error, and player technique can outweigh a calculator or checklist. Where manufacturer instructions exist for the exact hardware, use those instructions and record the revision consulted.

Safety and stop conditions

Stop for abnormal resistance, cracking, heat, odor, electrical sensation, moving wood or joints, a measurement that cannot be repeated, or any step that would remove material without a confirmed cause. Secure strings and stored mechanical energy before hardware work. Refer structural, fret-cutting, mains-powered, or uncertain repairs to a qualified technician.

Related workflow

• Nut String Spacing Generator — Compare equal-center and equal-edge-gap nut layouts from real string diameters.
• Saddle Radius Planner — Calculate relative saddle-center targets from radius, string spread, action, and gauge.
• Equal-Center vs Equal-Edge-Gap — Compare two spacing definitions before marking.

Open the related page that answers the next unresolved question; do not run every tool as if every system needs adjustment.