Guitar Potentiometer Guide: How to Choose the Right Bushing Diameter & Height

Whether you are upgrading your guitar’s electronics, installing a new set of pickups, or simply fixing a scratchy volume pot, finding the right replacement potentiometer can feel surprisingly tricky.

While resistance values (250K vs. 500K) and tapers (Audio vs. Linear) get most of the attention, physical fitment is where most DIY modders get stuck. There is nothing more frustrating than opening up your guitar’s cavity only to find out your new pots don't fit through the pickguard or control plate!

In this guide, we’ll break down everything you need to know about potentiometer thread bushing diameters and bushing heights so you can pick the exact right fit for your instrument on the first try.

1. Bushing Diameter: Imperial vs. Metric (3/8" vs. M8 vs. M9)

The first step in choosing a potentiometer is matching the thread bushing diameter to your guitar’s existing mounting hole cutouts.

Imperial 3/8" (~9.5mm)

• Best For: USA-made Fender®, Gibson®, CTS®, and American standard builds.
• Hole Requirement: Requires a 9.5mm to 10mm mounting hole cutout.

Metric M8 (~8mm)

• Best For: Asian-made Squier®, Epiphone®, and entry-level import ST/TL/PB/JB style guitars.
• Hole Requirement: Requires an ~8mm mounting hole cutout.

Metric M9 (~9mm)

• Best For: High-tier Asian electric guitars and basses made in Korea, Japan, or China (e.g., Ibanez®, ESP® / LTD®, Schecter®, Jackson® Asian lines, Cort®)
• Hole Requirement: Requires an ~9mm mounting hole cutout.

Pro Tip: If you are installing USA-spec Imperial 3/8" pots into an import guitar (like a Squier or Epiphone), you may need to slightly ream or enlarge the mounting holes on your pickguard or wood body from 8mm to 10mm.

2. Bushing Height: Short, Medium, or Long Shaft?

Once you know your diameter, the next critical measurement is the Thread Bushing Height (the length of the threaded portion of the shaft). Picking the wrong height means your pot will either be too short to thread a nut onto, or stick out way too far from the body.

Quick Compatibility Reference Table

Thread Bushing Height	Compatible Guitar Models	Dimension Diagram
Short Shaft (6.5mm / 1/4")	• USA / Import Fender® & Squier® ST/TL/PB/JB pickguards • Metal Telecaster® & Bass control plates • Thin body cavities
Medium Shaft (9.5mm / 3/8")	• Flat-top Stratocaster®, Telecaster®, & Precision/Jazz Basses® • Standard cavity depths across Ibanez®, Schecter®, & ESP®
Long Shaft (19mm / 3/4")	• Gibson® & Epiphone® Les Paul® (Carved Tops) • Thick custom wood-top builds

3. How to Choose in 2 Simple Steps

To make your ordering process foolproof, just follow this 2-step checklist:

1. Check Your Mounting Surface (Where is the pot installed?)

• On a Pickguard or Metal Plate? ➔ Choose Short (6.5mm) or Medium (9.5mm) height.
• Through a Thick Carved Wood Body (like a Les Paul)? ➔ You MUST choose Long (19mm) height.

2. Check Your Guitar's Origin (What size is the hole?)

• USA Specs (Fender/Gibson): Imperial 3/8" (9.5mm).
• Import / Asian Specs (Squier/Epiphone/Ibanez): Metric M8 (8mm) or M9 (9mm).

Summary Checklist Before Buying

Before clicking "Add to Cart", double-check these 4 parameters:

• Bushing Diameter: Imperial 3/8" (9.5mm), Metric M8 (8mm), or Metric M9 (9mm)?
• Bushing Height: Short (6.5mm), Medium (9.5mm), or Long (19mm)?
• Resistance Value: 250K (Single-coils) or 500K (Humbuckers)?
• Shaft Type: Split Knurled (for push-on knobs) or Solid Shaft (for set-screw knobs)?

By matching both the diameter and bushing height to your guitar's exact body specifications, you'll enjoy a smooth, hassle-free installation and pro-level wiring performance!