I'm trying to build a step stool that has a rotating chair back that will rotate from top position (e.g. chair) into bottom position (e.g. step stool). I do not want a free rotation of the chair back so I want to avoid it slamming on the floor. I've been looking for a bearing that acts as a mechanical stepper to click every 15 degrees with enough force requirement to stop the chair back from falling to the ground without force being applied (other than gravity).
I've been searching google for a while now and cannot figure out what this part would be called.