Hi Sav2319...

Once the knob comes off, that's it! You need to fashion another replacement, such as a volume control knob, muffler knob, etc. I've used the large Slingerland muffler knobs, drilled out to 5mm and then press fit onto the existing shaft. However, the shaft splines on the end need to be in good condition to hold the knob. Hope this helps.

-Mark

Ah damn, good to know though. I might just try that then, tone control knobs might be a little easier to find. Thank you idrum4fun!