As you know, along with the obvious positive properties of the collet legs of a compass also has its drawbacks: requires the stylus is of a diameter; and if it is broken — remove it not so easy; adjusting the length is difficult, and so on. Not to mention the fact that it is impossible, for example, instead of the stylus to charge, say, a ball stud.
That’s why I refused collets, replacing it with several clamps of different diameters (like school goat legs), pripal each of them to the holder — rod of suitable diameter, inserted instead of the collets.
Now you can “charge” the compass of any pencil, ball pivot, and even marker.
N. SEDOV, Izhevsk