Potentiometer Mounting Fit Checker

What this tool is for

Check a measured pot bushing, panel stack, and body depth before ordering or altering a guitar. 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

Disconnect the guitar, photograph the wiring, and measure the smallest clear mounting hole, total panel stack, exposed threaded bushing, pot body, terminals, and usable cavity depth. Use the exact candidate drawing.

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 mounting-hole diameter: records the actual string dimensions or supported set rather than a visual estimate.
Candidate bushing diameter: records the actual string dimensions or supported set rather than a visual estimate.
Panel / top thickness: provides a measured or counted input; confirm the allowed range and repeat the reading before relying on it.
Threaded bushing length: supplies a measured geometric quantity whose datum and resolution should be written down.
Outer washer and nut stack: provides a measured or counted input; confirm the allowed range and repeat the reading before relying on it.
Candidate body depth: provides a measured or counted input; confirm the allowed range and repeat the reading before relying on it.
Available cavity depth: provides a measured or counted input; confirm the allowed range and repeat the reading before relying on it.
Required free-space allowance: 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

A clear result applies only to the entered cylindrical and depth envelopes. Compare the body diameter, anti-rotation tab, solder lugs, wire bend, knob height, and current-scale drawing before ordering or dry fitting.

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 checker subtracts candidate bushing diameter from the existing hole, subtracts panel plus outer hardware from available thread, and subtracts body plus allowance from usable cavity depth. Each interface must clear independently.

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

A 9.8 mm hole around a 9.5 mm bushing leaves 0.3 mm diametral clearance. A 9 mm thread crossing a 6 mm panel and 1.5 mm washer/nut stack leaves 1.5 mm, while a 25 mm cavity around a 24 mm body plus 1 mm allowance is exactly at the boundary.

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

Hole roundness, taper, finish chipping, body diameter, terminal orientation, wire stiffness, nut engagement requirements, conductive shielding, and tool access are omitted. Never enlarge a hole from this result.

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

Knob & Pot Shaft Compatibility Checker — Compare knob attachment, bore, spline, and engagement with a measured pot shaft.
How to Measure Guitar Control Hardware — Record panel, hole, component, cavity, and coordinate datums before ordering.
Metric vs Imperial Guitar Control Hardware — Compare measured interfaces instead of relying on import or US labels.

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