I have burned through 5 bits trying to drill into my bathroom floor in order to secure a new repair flange. The top layer is marble, which I’ve drilled through with a Tapcon carbide tipped concrete bit. Since then I have tried every type of bit: black oxide, cobalt, titanium, carbide, glass & ceramic tile - and finally - a $15 Milwaukee Diamond Max 10x Life bit for porcelain, tile & stone. Even the diamond bit was worn down to a nub as smooth as a baby’s ass in a couple of minutes. Yes, I followed directions, tutorials, drilled slowly, with steady pressure and kept the bit cool. No, I’m not an idiot. I’m guessing there is vintage Chicago hex pattern mosaic porcelain under the marble, but a diamond bit should still be able to do the job, right? What manner of adamantium devil craft am I dealing with here? I am on day 3 of this hellish nightmare. Now I know why the previous installer used such a half-assed, jury-rigged solution to mounting the toilet with no flange. Thoughts/suggestions/advice appreciated.
Trouble Drilling Holes for Flange Repair
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I use a rotohammer very gently. It's a bit expensive to have as one of your tools, but I use mine often for what I do.
For sure, it's frustrating making holes in very solid material. I sometimes start with a small hole with that, and then go larger. Always worried about the flooring I'm going through.
For sure, it's frustrating making holes in very solid material. I sometimes start with a small hole with that, and then go larger. Always worried about the flooring I'm going through.
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Could it be porcelain that looks like marble? Marble is not that hard.
Are all of the holes over the hard-to-drill stuff? Are there holes in the ring part, rather than the ears, that are over something easier to drill?
As I noted, I got through the marble and I believe the next layer probably is porcelain. Thanks for the alternate hole suggestion. There are indeed 4 other holes on the ring itself, but unfortunately I ran into the same issue with them. This Suuuuuuucks!
Thanks for the quick reply, boss. Probably can’t spring for the Roto. I do have a hammer drill, but was afraid I’d just crack the tile. I did try small first with no luck. Literally erased the blade on an 1/8” ceramic & glass bit in seconds. And the smallest diamond tipped porcelain bit I could find was 3/16”.
Jadnashua
Retired Defense Industry Engineer xxx
Diamond core bits tend to work decently IF you keep them wet and don't press too hard. Keep in mind that a diamond bit is literally grinding the hole, not cutting it like a twist drill does, so you need to go fairly slow. If it gets too hot, or you apply too much pressure, you'll break the bonds between the diamond chips and the metal support. THen, it's metal trying to cut...doesn't work as it's usually softer than the material it's trying to cut. If you have porcelain underneath, a high quality porcelain is close to a synthetic sapphire, almost as hard as diamond.
There are some diamond bits designed to be used dry, but they will wear out faster.
There are some diamond bits designed to be used dry, but they will wear out faster.
Thanks for the reply. I went very slowly, about 2 revolutions per second at first. I could make out the markings on the bit. Then sped up a little at a time to maybe 200 revs/min. And I kept the hole and bit wet with a spray bottle set on stream. It still wore down (diamond came off the bit, as you said) in short order. I can’t imagine my pressure was too hard - light to medium in my estimation, but who knows. I’m at a loss. Thanks again for your info.
If you cracked the porcelain, wouldn't the crack be double-hidden?
Most of the time, yes.
Not always. Sometimes you have large tiles that extend out a ways.
Jadnashua
Retired Defense Industry Engineer xxx
I drilled some holes with a hammer drill in some hard porcelain with a carbide bit. It didn't really cut it, but more like hammered a hole in it. The bit was toast afterwards, but I got a half dozen holes out of it. If the subfloor is solid and the tile has good coverage underneath (industry standards call for at least 90% of the bottom and 100% of the edges should be covered in thinset, cracking it shouldn't happen, but, no guarantees. Some bits are better than others.
