Advice sought - Selector switch knob repair

[ClockChip]

Hello Everyone,

I am seeking to repair a knob on an old (circa 1971) Panasonic clock radio (a model RC-6900). The good news is that I have the small, easily lost knob. The bad news is that the knob has come off a slotted post and I need to re-attach it in such a way that I won't have to worry about it coming loose again.

Here is a picture of the bare slotted post (if I have the term right) the knob should be attached to:



As you can see, this is an Old School selector switch, which means it's pretty stiff. Put another way: the knob has to fit very snugly on the post in order for it to work properly over the long term. Any play in the fit and I risk the knob coming loose again over time (or breaking off altogether).

As for the knob itself, here is a picture of the interior:



The slot you see is 1mm thick, 5mm high, and 9mm in depth.

My question is: does anyone know of a small piece of metal something-or-other approximately that size that I could work with a file so that it forms a tight friction fit?

Apart from manually filing down a small piece of metal to get it to fit tightly in that slot, I have no idea how to effect this repair in such a way so as not to damage the knob. However, if you, the person reading this, do have an idea, I am all ears.

Long story short, I am hoping this is something I can pull off with a file, a small bit of metal, and some patience - I do not have access to a Dremel or any sort of power tool to help speed things along and my budget for this, all told, is about $20 (give or take). However, what I lack in tools I can make up for in time and I don't mind spending a day or three patiently filing down a bit of metal if that's what it takes.

Any suggestions?

[R_J]

There is a small spring steel clip that is missing it fits in the knob slot and goes between the split in the shaft, something like this. You could try using a piece of stiff plastic to make it as well

[sam_sam_sam]

There is a small spring steel clip that is missing it fits in the knob slot and goes between the split in the shaft, something like this. You could try using a piece of stiff plastic to make it as well

And or use hot glue to keep it in place hopefully you do not need to remove it for some reason later down the road because of some kind of repair

[redwire]

I usually see a knob like that with a small steel pin in that slot. It ends up in the shaft slot, splaying it enough so the knob grabs tight.
If it fell out and vanished, check the knob for cracks. The pin is hollow, it's like a keyway or something. I would find the exact diameter rod and cut a short piece. Coathanger is a bit too big I think.
Hobby store will have what you need.