Hammer mode is how tiles die
Percussion on a glazed or porcelain tile causes catastrophic shock cracking. Rotary only — always. If the bit will not cut, the answer is a better bit and water, not hammer.
04
400–1,000 rpm
Porcelain (wet)
300–500 rpm
Ceramic (wet)
never
Hammer mode
45°
Start angle
01 — At a glance
The three things that matter most
Porcelain is dense, glassy and unforgiving: it chips from vibration, cracks from shock and dulls a bit by polishing the bond over the diamond. Four habits — tape, low speed, water, and a 45° start — turn a risky job into a routine one.
Start at 45°, then straighten up
Hollow electroplated hole saws have no pilot point. Spin the bit up first, touch the leading edge to the tile at 45° to grind a crescent “smile” in the glaze, then pivot upright to 90°. The bit locks into its own groove.
Water — or wax, but never dry and fast
Water is mandatory on sintered and electroplated bits; vacuum-brazed wax-filled bits tolerate dry indoor work. Either way: low speed, light pressure. Heat melts the bonding matrix and the tile cracks.
02 — Tool matching
Match the tool to the material
Pick the row for your material. If two rows look similar, start with the slower option — it is almost always the safer and cheaper mistake.
| Tile | Recommended bit | Speed | Cooling |
|---|---|---|---|
| Ceramic tile | Carbide-tipped or diamond | 300–500 rpm | Wet (recommended) |
| Porcelain / porcelain slab | Diamond bit or diamond hole saw | 400–1,000 rpm | Water mandatory |
| Glass tile | Diamond, fine grit | very low | Water dam |
| Natural stone tile | Diamond bit matched to stone | 300–600 rpm | Water |
| Large-format porcelain slab | Diamond hole saw + guide | 400–800 rpm | Water + template |
| Straight cuts in tile | Continuous rim diamond blade | 25–30 m/s | Wet |
03 — Step by step
A chip-free hole, step by step
In order. Skipping a step usually costs more time than it saves.
01
Mark, tape and protect the glaze
Pencil or wax marker for position, then a piece of masking tape over the spot. The tape adds grip and stops the bit skating on a polished surface, and it protects the decorative layer. Stay at least 50 mm away from any corner — edges and joints are the weakest part of the tile.
02
Check the tile is properly bonded
On a new installation, wait 24–48 hours after fixing. A tile that is loose or on uncured adhesive will crack no matter how good your technique is.
03
Spin the bit up before contact
Start the drill at low speed and only then bring it to the tile. Touching a stationary bit to the surface is how you scratch the glaze and let the bit wander.
04
The 45° launch
Hold the bit at 45° to the surface and grind a small crescent groove into the glaze. Once the bit has bitten, pivot slowly to 90° — it is now locked in its own channel and cannot wander.
05
Flush with water continuously
Use a spray bottle, a wet sponge, or a clay/putty ring to hold a shallow pool on a floor tile. Keep the water going for the whole hole; the only job of the pause is to let heat escape.
06
Ease off through the back face
Reduce pressure as you break through so the exit face does not blow out. On wall tiles, hold a sponge around the bit to stop water running into the wall cavity.
07
Dress the bit if it stops cutting
If the bit just spins without progress, the bond has glazed over the diamond. Drill into an abrasive stone, cinder block or brick for 5–10 seconds to strip the polished layer and expose fresh diamond grit.
04 — Feeds & speeds
Numbers to start from
Use these as a starting point and adjust to what the cut is telling you. Start slow and work up.
| Operation | Speed | Cooling | Common mistake |
|---|---|---|---|
| Diamond bit in porcelain | 400–1,000 rpm | Water, continuous | Hammer mode → cracked tile |
| Carbide bit in ceramic | 300–500 rpm | Water (beneficial) | Too much pressure on the glaze |
| Diamond bit in glass tile | 300–500 rpm | Water dam | Speed → edge chipping |
| Plunge / start on glazed tile | low, spinning first | Water | Starting a stationary bit → slip |
| Continuous rim blade, tile saw | 25–30 m/s | Wet tray | Feeding too fast → chipped edge |
| Angle-grinder tile blade | per blade rating | Wet if possible | Dry cutting porcelain → thermal cracks |
05 — Troubleshooting
If it goes wrong
The symptom is rarely the problem. Read the root-cause column before you change anything.
| Symptom | Root cause | Fix |
|---|---|---|
| Bit spins but makes no progress | Glazing — the metal bond has polished over the diamond | Dress the bit in an abrasive stone, cinder block or brick for 5–10 seconds, then resume |
| Chipping around the hole | Too much speed or pressure, no tape, or drilling near an edge | Tape the spot, lower the rpm, light pressure, keep at least 50 mm off corners |
| Tile cracks (sometimes audibly) | Hammer mode engaged, too much pressure, or an unsupported tile | Rotary only, steady light pressure, support the tile on a flat surface |
| Bit wanders across the glaze | Smooth glazed surface, no tape, no guide | Masking tape or a wooden template with a pre-drilled hole to guide the bit |
| Hole edge blows out on the back face | Pressure kept up through breakthrough | Ease off for the last few millimetres; drill from both sides on a loose tile |
| Burning smell, bit discoloured | No coolant | Water — or for wax-filled bits, let the wax do the work and do not force the cut |
06 — Recommended tools
Bits and blades for tile
Every item below is made by EXTRACUT and links straight to the product page.
Glass and Tile Drill Bits
Glass and tile drill bits — precise small holes without cracking the glaze.
View product
Glass and Tile Drill Bits Blue Tip
Blue-tip glass and tile bits for harder porcelain and stone tile.
View product
Electrical Plated Diamond Hole Saw Hole Cutter
Electroplated diamond hole saw for tap, pipe and socket cut-outs.
View product
T.C.T. Hole Saw
T.C.T. hole saw for faster cutting in ceramic and softer tiles.
View product
Continuous Diamond Blades
Continuous rim diamond blade for straight cuts with a clean edge.
View product
Vacum Brazed Diamond Polishing Pads
Polishing pads to finish cut edges and restore a shine.
View product
Multi Functional Drill Bits
Multi-functional bits for mixed light masonry work where tile is not the only material.
View product
Bi-Metal Hole Saw
Bi-metal hole saw for the substrate behind the tile when you need the fixing to go deeper.
View productElectroplated and vacuum-brazed diamond, plus T.C.T. hole saws for the softer tile work.
07 — Safety
Before you switch anything on
Short list, long consequences. These apply to every job on this page.
Porcelain dust contains respirable silica. Wet drilling suppresses it. If you must drill dry, use local extraction and a mask.
Eye protection is non-negotiable. Tile shards are sharp and travel — add gloves for handling cut edges.
Water and power tools need RCD/GFCI protection. On walls, hold a sponge around the bit so water does not run into the cavity.
Support the tile. Drill on a flat, stable surface, or on a wall where the tile is fully bonded and cured.
Do not drill close to a corner or a grout line. Stay at least 50 mm from edges wherever the fitting allows.
Let the bit cool. Warm is normal; too hot to touch means the bond is being damaged.
08 — FAQ
Frequently asked questions
The questions our technical team answers most often.
Can I use a normal masonry bit on a tile?
No. A standard masonry bit is too hard and blunt for a glazed surface — it will not penetrate the glaze and will shatter the tile when you push. Use a carbide bit for ceramic, a diamond bit for porcelain, stone and glass.
Do I have to use water?
For porcelain, glass and natural stone, yes — water is what keeps the bonding matrix below the temperature where it fails. For soft ceramic, wet drilling is still recommended because it extends bit life and controls dust.
How do I stop the bit slipping at the start?
Masking tape over the spot, spin the bit before contact, and start at 45° to grind a small groove before straightening to 90°. A wooden template with a pre-drilled guide hole works for repeated holes.
Why did my diamond bit stop cutting?
Glazing. The metal bond polished over the diamond grit. Dress it by drilling into an abrasive block, cinder block or brick for 5–10 seconds — the abrasive strips the polished layer and exposes fresh diamond.
Can I drill through tile that is already on the wall?
Yes, if the tile is fully bonded and cured. Stay away from edges and grout lines, use a sponge to contain water, and consider a template so consecutive holes line up for the fitting.
Still not sure which tool fits the job?
Send us the material, the machine and the finish you need. Our engineers will specify the blade, bond or bit — and quote it with a sample if you want to test before you commit.