Just a quick tip for a fast, and cheap way to add some resistance. I had some gray foam left from a case that had "pluck foam". I wrapped a strip of the foam around the post, put the knob back on and then tucked any excess foam into the pot with a butter knife. It's not quite as pretty as the rubber grommets as you can see some foam if you look closely, but it works, was free and done in under 10 minutes.