Doing some touch ups on an RCA Sweet 16 Sportabout. I have one knob that was replaced with a similar but incorrect one in the past, and I managed to track down one of the correct style. Each knob has what I'm calling a "ring lock" (until I know the correct name) holding it to a number plate, and I have no idea how to remove them. Does anyone know what approach I should be taking so I don't ruin the shaft?

Why would you want to remove the number plate of a knob?

I have two knobs, each with attached number plates. One is the original number plate for the TV, but at some point the knob was swapped. The other is the correct knob, but with the wrong number plate.

You can see in the picture that the VHF and UHF knobs don't match. They're supposed to. The circular sections and number plates do, but not the part you grip. That's what I'm trying to swap.

I have two knobs, each with attached number plates. One is the original number plate for the TV, but at some point the knob was swapped. The other is the correct knob, but with the wrong number plate.

You can see in the picture that the VHF and UHF knobs don't match. They're supposed to. The circular sections and number plates do, but not the part you grip. That's what I'm trying to swap.

You have to pry up on most or all of the gripper fingers on the retaining ring, that hold the number plate to the knob shaft. A bit of patience is needed.
Also, make sure that the numbers line up, with the tuner position. You don't want to put the retaining ring back on, only to find out that the numbers don't line up. There should be a keyway on the number plate, but you never know. :scratch2:

Do you recommend a tool?

You have to pry up on most or all of the gripper fingers on the retaining ring, that hold the number plate to the knob shaft. A bit of patience is needed.
Also, make sure that the numbers line up, with the tuner position. You don't want to put the retaining ring back on, only to find out that the numbers don't line up. There should be a keyway on the number plate, but you never know. :scratch2:

But if you do break it or can't pry it off you can snap it with a side cutter and replace with a new one. Most hardware or Lowes type stores should carry them. They are called round spring nuts or push nuts. I think i've gotten them at auto parts stores also.

Do you recommend a tool?

I guess, I failed to mention a tool. I used, either an ice pick or a smaller jeweler's screwdriver. You have to bend the fingers up, just a bit to make the ring slide off the shaft. The ring is made of spring steel.
As I mentioned before, it takes a bit of patience. You might have to use two tools, one to pry the fingers and one to lift the indicator disc, the length of the shaft.

Sometimes, when you get the ring off, there's a keying tab (like the keying tab on an octal tube centerpost). If the new plate doesn't line up correctly, you have to cut the tab away, and epoxy the plate in the correct position. Replacing the ring then becomes optional (or moot).

Done!

Never again.