Replacement oscilloscope Knobs?

[JRC75]

This might be a good candidate for a 3D printed part.

Or a self casting.

 

[Scott75s1974]

I'd try some heatshrink tubing on the shaft.

 

[WntrMute2]

maybe try wrapping the splines with teflon tape. One wrap at a time until you get the fit you wanne.

 

[TriodeLuvr]

After playing with this for several days, it turns out the knobs can be made to work if a small piece of clear tape is stuck to the control shafts to increase their thickness. I cut the tape so it's the same length as the splines, but it only wraps around about one-third of the shaft. This gives the knobs a good grip, and there's no problem using them for the pull-push functions. Hopefully this will be a good long-term solution.

 

[Oerets]

Once on a old scope used a rubber grommet that fit to work a situation like yours. Never did replace the broken knob. Should of saved the other knobs when it finally went south.
Alas did not.