1974 Precision Can o'Worms (Knob Adventures)

So I thought I would put some different knobs on the 1974 P bass that I got on
Reverb not too long ago. The brass ones that it came with are sorta cool, but not quite the right match in terms of color or accuracy (the dome, the hex screws).



So I bought some Fender flat top knobs and aged them to match the distressed body—first with vinegar, then with ammonia, and then (when those two failed to deliver results) with muriatic acid.



Finally they were ready, and I took off the brass knobs. Surprise, surprise! The first thing I noticed were the split shafts, which (I’ve just come to discover) are not factory spec (and technically not meant to work with screw-mounted knobs). So these clearly were replaced at some point. Then, when I went ahead and attempted to put on my new knobs anyway, I discovered that one of the shafts is larger—and the threaded part goes way through the pickguard. The knob won’t sit down on the pickguard.



No worries, right?—I’ll just lower it and mount in place with a second nut. So I removed the nuts and washers, only to find that the pot shaft appears to be screwed into the pickguard rather than mounted with the nut tension. I can wobble it a little bit side to side, but I can’t push it through. So now it becomes a question of “Is the knob idea worth desoldering this pot, unscrewing it and mounting it in a more correct manner? And then the obligatory follow-up question: “As long as I’m at it, should I replace both pots with solid shafts?” It’s not like there’s some degree of vintage accuracy I am trying to protect. The bass has clearly had a lot of work done; I would say only the wood, truss rod, tuners and bridge look original. (And maybe the pickguard screws?)

Bottom line: the bass plays and sounds fine, and I'm not on a mission to restore in any sense other than making the knobs a little original-ish. So can I just bore out some of the bottom of my knob (on the right) so that it will fit over the threaded part of the shaft like the brass knob (on the left) does?



And lastly, now that I've become aware of the undersized shaft on the volume pot, I'd love to find a way to make the knob not wobble in an elliptical orbit as I turn it. Like, can you put a sleeve over the smaller shaft and make it into a larger one?

 

Brilliant. This is exactly the kind of Beautiful Mind solution I was hoping I would come up with, but didn’t. Thank you!!

 

So (thanks again to sissy kathy) here's the job all done—for now. Looks a little less dolled-up and a little more "right" to my eyes. (But I'll probably keep the brass knobs in case I want to go back at some point.)

I ordered some of those sleeves and will do that little additional fix. And the seller of those sleeves also had a wiring kit with CTS solid-shaft pots and a .1uf ceramic disc capacitor, so I snagged those for that point down the road where I'm feeling ambitious. It would be nice to have things be correct under the hood (but not necessarily this month, haha).