Fitting knobs on pot shaft spline knurls that don't match

[StarryNight]

does anyone have any smart way to fit a pot knob with course knurl over a pot with a fine knurl shaft? so frustrating that it's not universal!

[Mick Bailey]

For thermoplastic knobs I use a shaft removed from an old pot which I close up very slightly. Heat it up just enough so that it will soften the plastic, push it in then remove it quickly. The best way is to press the shaft in an extension and mount in in the drill press (I use my lathe as it has a fast acting lever feed tailstock) which keeps everything in line. It works fine by hand though if you keep everything straight and don't overheat the shaft. Try it first on a spare knob to see if it's the method for you.

[StarryNight]

For thermoplastic knobs I use a shaft removed from an old pot which I close up very slightly. Heat it up just enough so that it will soften the plastic, push it in then remove it quickly. The best way is to press the shaft in an extension and mount in in the drill press (I use my lathe as it has a fast acting lever feed tailstock) which keeps everything in line. It works fine by hand though if you keep everything straight and don't overheat the shaft. Try it first on a spare knob to see if it's the method for you.

I was thinking of this very same method using my mill. great, i will give it a go thanks!

[StarryNight]

follow up: worked pretty well. the heated pot shaft went into the pot like butter. I had to move pretty fast though, i left it a second too long and it got stuck in there. with a little prying I got it loose.

[Mick Bailey]

That's the method! Happy it worked out for you.