How does a collet knob work for a Potentiometer??

I have a 6.35mm smooth shaft Potentiometer and looking for a knob to go onto it. I've seen the set/grub screw type, i get how they work but worried about slipping.

Also seen the collet type but not to sure how they clench down on the shaft. The shaft isn't threaded, as just a groove running along the top of it. Would it work like a conventional collet from say a dremmel tool?

Why not use Locktite on the shaft before mounting the knob ? One drop should be enough.
At work they have a vice and ussually use a large file to put a flat spot on the shaft. I've done it with small files too.

At least some have a compression washer so more like a plumbing fitting than a dremel chuck.

Also seen the collet type but not to sure how they clench down on the shaft

The ones I've used have a removable cap on the front of the knob. Once that's off, you can tighten the collet with a screwdriver and then replace the cap.

Hey cool for all the replies, only need two so will try the collet type, depends on style and availability. Yes i did think about filing, well grinding a flat spot. Cheers