Bathroom tile can be a difficult material to work with. I installed Moen grab bars in the master bath with the bar half behind the shower and half outside. The outside was simple, I used a block of 4 1/4" x 4 1/4" birch plywood on the outside of the drywall to align the two mounting surfaces - the holes in the birch plywood and drywall were made using a standard hole saw. at 1 1/4". For the tile, I chose to drill it at "four corners" + with this Remgrit carbide hole saw so that (A) it was easy to start grouting, and (B) the saw stays relatively evenly on four corners It worked like a charm. The slowest drill speed was just enough to remove material and a slow feed did the trick. I cut off the four tops of four tiles and got a perfectly smooth one and round hole..I would advise anyone using this hole saw to first cover the areas where the cut will be made to avoid possible surface chipping - this is not a problem in my case as the safety bar guard plates are wide the hole I cut has other materials sticking out like drywall and wood so make sure you do it yourself or make sure you have all the right tools.