With a drill they installed a handicap bar on the wall of a tiled shower stall. I followed a previous reviewer's recommendation to dip the drill in a cup of ice water about every 10 seconds to keep it cool. I also started at a 45 degree angle and moved up to 90 degrees once I got a good tile bite. was able to pry the drilled dowel out of the bit core with a small screwdriver inserted into the slot on the side. Once I got through the tile I used the shovel to finish drilling the drywall. The size was correct for 1/2" wall anchors.