The Right Diamond Hole Saw for Porcelain Tile — And How to Use It

Porcelain doesn’t care about your schedule. It’s dense, it’s brittle, and it will crack straight across a tile that was perfect thirty seconds ago. The fix isn’t more pressure or a steadier hand. It’s a diamond hole saw for porcelain tile, and understanding why diamond is the only honest answer to this problem. Here’s what’s actually going on, and how to cut a clean hole the first time.

Why Porcelain Tile Fights Back

Porcelain is fired hotter and denser than standard ceramic. That’s exactly what makes it good on a floor, it doesn’t absorb water, it doesn’t wear, it shrugs off everything a bathroom throws at it. It’s also what makes it miserable to put a hole through.

Two things go wrong. The tile is hard enough that most cutting edges simply skate across the glaze instead of biting in. And porcelain is brittle, so the moment something does bite in hard, it wants to fracture rather than yield. You get a chipped crater on the entry side, a blowout on the back, or a crack that runs off the edge and takes the whole tile with it.

You’re not trying to cut porcelain. You’re trying to grind your way through it in a controlled way. That takes a different kind of edge.

Diamond Is 10 on the Mohs Scale

Diamond is the hardest naturally occurring substance on Earth. On the Mohs scale of mineral hardness, diamond sits at 10. It’s literally the object every other stone’s hardness is measured against. Nothing in your bathroom outranks it.

That’s the whole argument. When the material you’re working on is near the top of the scale, you go to the top of the scale to get through it. A diamond edge doesn’t need to be sharp in the way you normally think about sharp. Thousands of exposed diamond particles abrade the porcelain away, a little at a time, without the shock loading that cracks tile.

At Bad Dog Tools we’ve been running diamond on our HDII Handi-Disc for more than ten years. When it came time to build a hole saw, diamond wasn’t a decision, it was the obvious choice. Our hole saws use the same 46-grit diamond that’s been proving itself on the HDII for a decade. Same abrasive, same standard, same lifetime guarantee behind it.

How to Cut a Hole in Porcelain Tile

Our diamond hole saws are built for angle grinders. They come with a 5/8-11 adapter that threads directly onto a standard grinder spindle. That’s on purpose. A grinder delivers the speed a diamond edge needs to work efficiently. Diamond grinds rather than slices, so surface speed at the cutting edge is what actually removes material.

1. Mark your hole. Sounds obvious. It matters more on tile or stone than anywhere else, because you don’t get a second attempt on a set tile. Mark the center and the circumference.
2. Thread the hole saw onto your grinder. The 5/8-11 adapter goes straight onto a standard angle grinder spindle. Hand tight, then check it’s seated.
3. Start at an angle at about 30 degrees. Don’t come in flat. A flat start lets the saw wander across the glaze. Come in at roughly 30 degrees so only a small arc of the rim contacts the tile.
4. Rock the saw into the surface. Gradually bring it upright as the rim cuts its own groove, until the saw is fully engaged and cutting on the whole circumference.
5. Let the diamond work. Steady, moderate pressure. Leaning on it doesn’t speed anything up, it just loads the tile you’re trying not to crack.
6. Ease off as you break through. The back side is where blowout happens. Lighten up on the last bit of material.

Should You Use Water?

Water helps, and we recommend it, but it isn’t required. A little water at the cut keeps dust down and keeps heat out of both the tile and the diamond. If you’ve got a way to trickle water at the cut or wet the surface as you go, do it. You’ll get a cleaner cut and a longer-lived saw. If you don’t, the saw will still get through. Just don’t dwell in one spot.

It Isn’t Just for Tile

Porcelain is where most people start, but the same 46-grit diamond handles a lot more. These hole saws cut porcelain tile, stone, concrete, masonry, granite, composites, and carbon fiber. They also work well on drywall and older horsehair plaster, which anyone working in a New England house older than they are will appreciate.

One set covers the tile job, the concrete anchor, and the plaster wall in the same afternoon.

Backed for Life

We’ve been making cutting tools in Bristol, Rhode Island since 1988. Three generations of the same family, and over six million bits produced. Everything we make is Made in USA.

Our diamond hole saws carry the same lifetime guarantee as everything else in the line. Dull it, damage it, get it back to us and we’ll replace it. You cover return shipping and handling; that’s it. We’re not interested in selling you the same tool twice.