What are collet knobs?

[Byron G. Jacquot]

>So, Rean has a bunch of knobs called "collet" knobs.. Says something about
having to adjust the collet? What kind of voodoo is this? 
>
>Yet another thing they did not teach at school.
>
>Please advise.

A collet knob is kinda like a little drill chuck.  They slide down over the
shaft, and then you turn a little screw in the face of the knob, which
tightens a little clamping mechanism.  They usually have a cover/cap that
goes on top, to cover up the screw.

They're fairly secure once they're installed right.  They dont ding the
shafts like set screws do.  You do have to be careful to get them to match
the shaft dimaeter you'll be putitng them on, and should be wary of any that
take special tools for installation