Replacing Knobs

[Adam Maloney]

I would like to replace the knobs on my peavey grind 6 string bass. Can I use any knob, or are they not universal?

[Jazz Ad]

There are 2 main shaft types, split and solid.
Take off the knobs and see what you have.
If the knobs are attached with a screw you have solid shaft. If they are force pushed in place they are split shaft.
Standard diameter for the shaft is 6 mm, it is used the most used but sometimes you get 3.5 mm.

[Steveaux]

In the U.S., split shafts are 6mm, solid shafts are 1/4".

[T-Bird]

Hi.

You have to look what You have, there's way more variables than the ones above.

From the more common in instruments variety, ~6mm there's:

6mm solid shaft
6mm splined (and usually, but not necessarily, split as well) shaft.
6mm beveled shaft.

1/4" solid shaft
1/4" splined (and usually, but not necessarily, split as well) shaft.
1/4" beveled shaft.

The beveled ones are less common than the others, found mainly on concentric potentiometers IME, but that's still more than enough variables to get it wrong.

IMLE the make and model without the exact date or year of manufacture doesn't ensure correct fit.

So, IME better to measure than guess.

Regards
Sam