Prewired Harness Layout Matcher

What this tool is for

Compare measured control-hole coordinates and cavity envelope with a candidate prewired harness. Control hardware fit tools compare user-measured interfaces and envelopes. They do not treat metric, imperial, model, or instrument-family labels as dimensions and never authorize drilling, routing, or forced assembly.

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

Choose one physical origin and axis direction on the guitar. Record every existing control-hole center and every candidate shaft center in the same order, plus the smallest usable cavity envelope and the complete harness envelope including wire allowance.

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

Input and display unit: sets the interpretation and display unit; do not mix units elsewhere in the same run.
Existing hole centers (x,y per line): captures the exact observation, list, or requirement that the result must preserve.
Candidate hole centers (x,y per line): captures the exact observation, list, or requirement that the result must preserve.
Allowed per-hole mismatch: provides a measured or counted input; confirm the allowed range and repeat the reading before relying on it.
Existing cavity clear length: supplies a measured geometric quantity whose datum and resolution should be written down.
Existing cavity clear width: supplies a measured geometric quantity whose datum and resolution should be written down.
Existing cavity clear depth: provides a measured or counted input; confirm the allowed range and repeat the reading before relying on it.
Candidate harness envelope length: supplies a measured geometric quantity whose datum and resolution should be written down.
Candidate harness envelope width: supplies a measured geometric quantity whose datum and resolution should be written down.
Candidate harness envelope depth: provides a measured or counted input; confirm the allowed range and repeat the reading before relying on it.
Wire allowance around envelope: 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

Coordinate and envelope passes are independent. Confirm point order and orientation, then overlay a 1:1 drawing or dry-fit the complete harness. A high residual can mean a real mismatch or a reversed/incorrect datum.

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 matcher translates candidate coordinates by aligning centroids, then reports each residual, maximum residual, and RMS residual without rotating or scaling the pattern. It separately compares the rectangular cavity and candidate envelopes.

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

Existing centers at 0,0; 30,0; 60,0 and candidate centers at 5,4; 35,4; 65,4 align after a translation of -5,-4 with zero residual. A candidate may still fail if its switch, capacitor, connector, or wiring exceeds cavity depth.

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

Rotation, mirroring, panel curvature, shaft tilt, component rotation, body shapes, wire routing, connectors, solder joints, shielding, and installation sequence are omitted. The output never authorizes redrilling or forcing a harness.

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

Potentiometer Mounting Fit Checker — Check a measured pot bushing, panel stack, and body depth before ordering or altering a guitar.
Control Switch Cavity Clearance Checker — Screen a toggle or blade switch opening, thread stack, underside envelope, and lever travel.
How to Measure Guitar Control Hardware — Record panel, hole, component, cavity, and coordinate datums before ordering.

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