First drill a small hole - 1/8" then move up to the 1/4". A hammer drill will help if the tile is really hard.

Bosch sells these bits at HD and other big box stores:

Tapping, gently, on the bit is the method used to break the glaze, the brittle surface created by the firing of the tile, and exposing the softer composite material easily penetrated by the bit.

In my experience, a pilot hole only increases the opportunity for the bit to wobble, and subsequent damage.

As snoopy said the key is to break through the glaze at the surface. I've used a centerpunch or nail set with success. Tapping the masonry bit works well.

Do not use a hammer drill.

A diamond core bit will not break the tile. They are relatively expensive, but probably less than having a tile man replace a cracked tile and then drilling a hole in it for you.

Drill the same size hole in a scrap of wood, then hot melt glue the scrap over where you want the hole. Place the diamond core bit in the scrap hole and drill. Remove the scrap and hot melt and you're done.

I've had very good success with a diamond drill, would not use a hammer drill on tile. I use the point of the drill held in my hand to scratch the center point --again, I don't like pounding on tile.

Thank you all. rwiegand: do you just twist the drill bit by hand to break through the glaze? Trebruchet, how does the wood help - to keep the drill from moving around? And then how do you remove the hot glue without pulling a tile off? I probably have some flexibility about where to put the screws in. Would it be better to aim for the grout lines? On second thought the grout is not going to be as wide as the hole needs to be. Sorry for being so dense, but I can't afford to mess this up!

"Trebruchet, how does the wood help - to keep the drill from moving around?"

Correct. Diamond hole saws have no pilot bit.

"And then how do you remove the hot glue without pulling a tile off?"

Whack it with a hammer sideways, or tap a scraper under it. A little acetone or alcohol will remove any residual hot melt glue. The tile will not be damaged which is the whole point.

I just finished drilling 8 holes into the walls of a very expensive porcelain tile shower. It was scary at first, but I managed to do it accurately and easily with nary a misstep. Here is what worked for me. First, I bought some inexpensive "diamond dust hole saws" in a 1/4 inch diameter. These drill bits don't drill a hole in the conventional sense, but they drill through the tile and take out a 1/4" wide, cylindrical core, leaving a clean 1/4" diameter hole.

In order to be accurate and prevent damaging the tile due to the bit "walking", I cut a small (about 5" X 5") piece of 1/4" thick plywood and first drilled a 1/4" hole in the center of it. I marked the tile where I wanted the hole, and then I centered the hole in the plywood on it and duct taped the four edges of the plywood to the wall. I then chucked the bit into my battery powered drill, sprayed a little bit of water from a spray bottle into the hole and started drilling; the water helps keep the bit cool and wear less. Every 20 seconds or so I would stop to check progress and spray a little more water into the hole. I used firm pressure, and moderate speed, and wobbled the drill around occasionally. After about 3-4 minutes the bit had made it through my very hard, 3/8" thick tile. There were no cracks, and no wandering due to the plywood guide. Once you are done with a hole, you may need to ram a nail through the center of the bit to eject the little tile core.The bits I used are cheapies from China, but they are good for a couple of holes before they start getting dull. Below is a link to the type of bit I used.

Here is a link that might be useful: Diamond dust hole saw

This post was edited by kudzu9 on Thu, Sep 25, 14 at 14:07

Well I just finished drilling about 20 holes in 3/8" thick hard porclain tile - with an 1/8" pilot and then a 1/4". And I used a hammer drill for the 1/8" hole.

How do you get the idea that a pilot hole will make the larger drill wobble?

All this messing around with gluing blocks of wood is IMO foolish. You'll be there all day and night.

Geoffrey-
I'm not clear on whether you are referring to my post or to several posts. However, if you don't use a guide of some sort, there is always the possibility that the bit will skitter across the tile, especially if you use diamond core bits as they don't have a point. Even the pros use guides. As for my guide, 20 seconds to tape it down and 10 seconds to remove it seemed like an easy insurance policy. And, when I wobbled the drill, it was intentional to get the drill bit to bite in around the whole circumference of the hole. I'm just not big on nicking the tile first or using a hammer drill. I'm glad you've had good luck, but I'm experienced with hammer drills and -- while they are perfect for some jobs -- think there is a possibility of cracking a tile using that tool.

Here is a link that might be useful: Drilling porcelain tile

This post was edited by kudzu9 on Thu, Sep 25, 14 at 20:47

In my experience, using a carbide drill bit at a grout line will cause more chipping than drilling further "inland" on the tile.
If you want zero chipping, and can put up with a lot of dust, a diamond "burr" will cut a very fine hole. Needs higher RPM than most drills will provide.
Casey

sombreuil_mongrel-
I agree...grout lines should be avoided if possible. If one is using a diamond burr, then having someone else spray it with water as you are drilling will cut most of the dust. If one uses the type of diamond bit I mentioned above, there is no dust if you go at moderate speed and spritz it occasionally with water. In fact, the water and wet dust form a slurry that traps additional dust and helps with the cutting action.

"All this messing around with gluing blocks of wood is IMO foolish. You'll be there all day and night."

Geoffery_B:

I drill freehand into stone countertops unassisted without failure regularly. The OP is scared of cracking a tile and is getting educated from YouTube videos. I'm fairly certain a bit of extra work to lower the odds of a bit skittering out of control is a small price to pay.

OOh, burn. Always a pissing match with some of you guys.

The problem with hammer drills is that true hammer drills cut as a rotary chisel, pounding and then rotating just a bit, pounding again, and so on. The hammering is their major function; they don't drill holes, they break holes. Very effective on concrete but really destructive if you goof even a little bit. A heavy duty hammer drill can shatter any tile no matter how well it's set. Hopefully nobody here is suggesting one of these things to drill a little hole in tile.

Most consumer grade hammer drills are really just drills, making their holes by spinning and cutting just like you do with a twist bit. The hammering is a very minor part of their function. This type can use those bits pictured waaaaaaay above very well.

Thirdly, it's pointless to give professional tips using professional tools and professional bits to a homeowner who just wants to drill a simple hole in a glazed soft ceramic back splash and not in a freaking 30 mm slab of quartz.

Simple answer that will work reliably: buy the exact size bit (like the ones in the pic) from a good maker (Bosch is good, no Harbor Freight!), chuck it in any drill, drill slowly, and take your time. That is it.

hammer drill...LOL!
I can take down a brick wall or make
a hole in a slab with my hammer drill...
but I'd shy away from using it on ceramic
or porcelain tile.

best of luck OP, take what you need,
ignore the rest. we got a full house today.

My favorite hammer drill "bit"
Casey

Here is a link that might be useful: spade bit

Casey-
That looks like it should do the trick!

Thank you all for your help. I made a 'jig" from a paint stick and hot glued it to the tile, bought a hole saw which wouldn't fit into my drill and ended up using a masonry bit. It took FOREVER to drill through that thin tile, but was neat and accurate, and ta da! Well, it was a big deal for me. I appreciate all of you who gave me ideas - and confidence to try this.

Well done!

good job..
should not require a hammer drill not a core type bit
unless the tiles were very hard..if no a simple tile drill bit..
done hundreds..the worse are the harder tile type
standard ceramic tiles..easy..just tile drill bit. used with water..like the Bosch
shown earlier..

now the harder question..do you got through the tile..
what are you holding the screws.lags screws into the tile with?
normal sheet metal screws are out..
plastic anchors? is heat a problem?
lead anchors?
toggle bolts?
lots of choices..some good or bad depending on the situation..
just asking what you used?
-dkenny

I used plastic anchors that fold behind the drywall. They were a little hard to get in because the hole was a little tight and they wanted to buckle, (I ruined a couple) but once in the screws pull them shorter making the little wings spread. We don't expect to have much weight on them but they were rated to 50 pounds each and I used 4. I don't expect heat to be a problem that high on the wall.....