The name Rock-Stop defines itself. The purpose of the rock-stop is to prevent the end-pin from rocking out of place. There are many types of rock-stops, but they all serve the purpose of stabilizing the end-pin on the cello and the bass.
The standard rock-stop most often used in school orchestras is a simple, round, rubber coated disk with an embedded metal inner disk. The tip of the end-pin is placed in the metal disk. The material on the bottom of the rock-stop creates a non-slip connection with the floor.
The rock-stop is nicknamed the “doughnut.”
There are many creative variations on the rock-stop theme. Because of the need to prevent the end-pin from slipping, trial and error have triggered various creative rock-stop designs. One of them has a strip of wood with carved-out groove notches in which to set the tip of the end-pin, supported by a strap system that attaches to the legs of your chair.
The End-pin and the Rock-Stop work together as a team, helping the cello and bass remain in secure contact with the floor.
Now, you need to learn how to determine how far you should extend the End-Pin!