Common Guitar Knobs Mistakes to Avoid

For something so small and seemingly simple, there are a surprising number of ways to get guitar knobs wrong. Not catastrophically wrong — nobody is blowing up an amp over a mismatched knob — but wrong in ways that waste money, cause frustration and occasionally result in a stuck or rattling control you did not have before. Here is what to watch for.

Mistake 1: Ignoring the Shaft Type

This is the most common and most avoidable mistake. There are two types of pot shaft — split shaft (serrated ridges, takes a push-on knob) and solid shaft (smooth, takes a set-screw knob). They are not interchangeable.

Fitting a push-on knob to a solid shaft pot will either not fit at all or will seat poorly and spin or wobble. Fitting a set-screw knob to a split shaft pot often works but can strip the soft metal ridges if overtightened. Before you order anything, remove an existing knob. If it has a small screw on the side, you have solid shaft pots. If it pulled off without a screw, you have split shaft. Match your replacement accordingly.

Mistake 2: Overtightening Set Screws

Set screws on solid shaft knobs are small — often 2mm Allen key or tiny flat-head — and the threads strip easily. Tighten to snug, not to the point of resistance. The knob should not wobble or spin freely, but you are not trying to torque it. Many players have stripped a knob or a pot shaft this way, which then requires either a new knob or a new pot.

If your set-screw knob still wobbles after tightening, check whether the screw is making contact with the shaft flat — some solid shaft pots have a small flat section on the shaft that the screw should seat against.

Mistake 3: Buying the Wrong Style for the Guitar

A bell knob (top-hat) on a Stratocaster-style body looks odd and may physically interfere with the pickguard or control plate depending on the height. A dome knob on a Les Paul will not look period-correct and may not fit the solid shaft pots. Style is partly aesthetic, but it is also partly about fit and function on the specific guitar.

Guitar knobs come in styles tied to particular guitar families — dome for Fender-style, bell for Gibson-style, speed for more modern instruments. If you are replacing like-for-like, match the style. If you are customising, check the height and diameter clearances before ordering.

Mistake 4: Damaging the Guitar Body When Removing Old Knobs

Pulling a push-on knob straight off with bare hands can scratch or chip the guitar's finish if the knob catches the body as it releases. The standard technique is to wrap a cloth around the knob and use a thin, flat tool under the knob's edge to lever it off slowly and evenly. Some players use two teaspoons, one on each side, lifting gently in parallel. Do not jerk or yank.

If a knob is truly stuck, warming it very slightly with a hairdryer (not heat gun — too hot) can expand the plastic just enough to release it.

Mistake 5: Forgetting That Knob Position Can Be Adjusted

On solid shaft pots, set-screw knobs can be positioned exactly — you can align the pointer or marker to the correct position before tightening. Many players forget this and end up with a tone knob whose "10" marker is off to one side or a volume knob whose indicator points the wrong way at maximum. Position first, then tighten.

On split shaft push-on knobs, the position is set by the serrations on the shaft. Push the knob on, check the pointer position, then adjust by pulling off slightly and repositioning on a different serration.

For a full overview of knob types and how they work, the guitar knobs explainer covers the details. New players should start with the beginner's guide for a gentler introduction.

The Bottom Line

Most mistakes with guitar knobs come down to not checking shaft type before buying, overtightening screws, or removing old knobs carelessly. Sort shaft type first, handle set screws with care, and use a cloth and lever technique to remove push-on knobs without touching the body — and you will have no problems.

Frequently Asked Questions