Removed 4 old knobs and 4 old grates. Replace with 4 new knobs and 4 new grates. Took about 3 minutes. Stove looks new again (it's 29 years old) and works great. I can fry eggs (and other foods) and not have them run together, and not have oil in one side of the skillet. No more tippy pans. Very, very nice!