[greco]

Spline count matters for the knobs.

I understand that but wonder if there is a workaround.

 

[greco]

Yes Dave, you should match the number of spline count of the pots and knobs. For example if pots are US spline count is 24 (based on: CTS - A500K LONG Split Shaft Pot)
if import then spline count is 18 (Alpha - Long A500K 18-Spline Pot)
and when you getting knobs you should follow the same pattern

Hope this helps

Sometimes when you are looking at knobs, the spline count is not always marked on the package.

 

[greco]

I have knobs you can try @greco

Thanks. This is for a guitar I'm working for a friend on and it has one missing knob and has one CTS pot.
He has purchased a new set of knobs which match the colour and style of the previous knobs.

Potentially damaging knob and/or pot and forcing it on there lol

What about drilling out the knob by 1/64 th inch?

 

[greco]

For what, the knobs?

Yes

 

[greco]

Avoid the whole issue and use knobs designed for 1/4" solid shaft pots with a set screw. Yes, they say not to (knurled knobs on knurled pots only) but like, been doing it for years and it's fine. Never really heard a good argument for it (against doing what I said) either. Both Traynor and Garnet did it (on plastic-shaft pots no less).

You are also less likely to rip out a pot shaft trying to get a press-fit knob off. That's happened to me with older/lower quality pots and tight-fitting knobs. This can also happen when a metric press on knob is forced onto imperial (it'll go, at least a bit, and then hard to get off). Spline count correlates with metric vs imperial shaft as implied above (i.e. 6mm vs 1/4" which = 6.35mm). If you only buy 1/4" knobs w set screws it will fit any pot shaft (ignoring the existence of 1/8" shafts - those are very uncommon in guitar gear, used mostly in older pro audio e.g. consoles and some rack gear .... and for those you can get a size-up collet or ideally appropriately sized knobs, but they ted to be harder to find and not cheap).

Flatted D shafts can be problematic unless they are oriented in exactly the right way to work w solid shaft knobs (set screw can't be in the cut away area of the shaft) so in that one case I would recommend using 'appropriate' knobs, unless you're a master kludger (I've done it but prefer not to).

Not everyone likes the looks of these knobs.

 

[greco]

Thanks everyone. I'll let the owner decide (logically) how he wants to proceed.

 

[greco]

UPDATE...

The fellow I was doing the repair work for brought over FOUR new knobs that matched the colour and style of the original THREE knobs on the guitar (one had been lost).

The pots were all original except for one which was clearly a CTS pot with the different spline count (and did not have a knob).

He randomly chose and pushed a knob on each pot from the SEVEN total and all went smoothly.

I assume we were lucky.