The grate pad pieces fit perfectly. Those I needed to replace had disintegrated, so the drill recommended to clean the holes was unnecessary: I scraped the holes to make sure there was no residue, put some adhesive into the hole, and pressed the new pads into place. One very good design feature is the tiny hole in the center of each pad, as it allows extra adhesive to squirt out when pressing the pad into place. Without the hole, the extra adhesive would be trapped, and wouldn't allow the pad to be easily pushed into the hole.