Grew up bobber fishing for steelhead on the river.
Take the metel springs off the bottom (where it connects to the line) and slip a piece of 1 inch surgical tubing over the stem. Roll the tubing back with your fingers, insert the line in the slot and then roll back over the line. Will hold nice and strong, allows you to slide your bobber up and down the line to make depth changes, and will not marr, cut, or cause abrasion to your lines. If it does tangle (weeds, trees, etc), the bobber will slide nicely down the line.
I have OCD "Obsessive Crappie Disorder"