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Diamond drill bit for porcelain

Updated: 2026-10-23

You are looking at a glazed porcelain tile, sometimes a 10 mm wall tile and sometimes a 20 mm patio slab, and the mixed set in the drawer includes a carbide spear. A diamond drill bit for porcelain has to grind that glaze. A ceramic technique and a carbide tip will polish or shatter it. This page stays on porcelain. The full order of shank, diameter and cooling is on the [diamond drill comparison](/hub/drilling-and-accessories/diamond-drill) and the buying guide. Glass and quartz worktops appear here only as a warning, because they are a different dust and breakage problem. A qualifying purchase can earn a commission at no extra cost to you.

You are looking at a glazed porcelain tile, sometimes a 10 mm wall tile and sometimes a 20 mm patio slab, and the mixed set in the drawer includes a carbide spear.

Our top picks

BRSCHNITT BRSCHNITT 32 mm M14

Best overall

BRSCHNITT BRSCHNITT 32 mm M14
9.0/10about £15.79
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DT-DIATOOL DT-DIATOOL five 6 mm M14

Alternative

DT-DIATOOL DT-DIATOOL five 6 mm M14
9.0/10about £24.99
View offer
Meccion Meccion 22 mm pilot saw

Best value

Meccion Meccion 22 mm pilot saw
8.4/10about £9.69
View offer
On this page
  1. 1.Porcelain is not ceramic
  2. 2.Thickness changes the pause
  3. 3.What in this sample is aimed at porcelain
  4. 4.Dust and the fitted tile

Porcelain is not ceramic

Ceramic wall tile is softer and often has a porous body under the glaze. A sharp carbide spear can open a small hole in that body if you are gentle. Porcelain is fired denser. Topps Tiles and CTD Tiles both point carbide at ceramic and diamond at porcelain. If your set includes a carbide bit, that piece is not the porcelain tool. Zeeorymn’s £5.99 pack is four wax-filled diamond bits plus a separate 6 mm carbide bit. UK reviews include buyers who say it will not cut porcelain. DKIBBITH’s pack adds a 6 mm masonry bit for the substrate after the tile is open, with hammer still off until you are clear of the glaze. Vacuum-brazed bits are the shape UK suppliers point at for many porcelain holes. If the rim is not diamond, it does not start the hole.

Thickness changes the pause

A 10 mm porcelain wall tile and a 20 mm porcelain slab are not the same minute of work. Würth’s UK dry M14 tile bit is described as particularly suitable to about 15 mm, with a pause after about 30 seconds once the material is thicker. That is Würth’s note for Würth’s bit, not a guarantee for the ASIN in your hand. On DT-DIATOOL’s five 6 mm M14 bits, one review reports about 20 to 35 holes in hard porcelain and another reports one and a half holes in 20 mm porcelain. On BRSCHNITT’s 32 mm bit, about 10 holes in 20 mm porcelain was called fair for £15.79. BGTEC’s 6 mm chuck bits buckled when a porcelain slab was drilled dry. None of those counts is a specification. If you are drilling 20 mm, plan the pause, keep the feed light, and do not expect the £5.99 set to finish the slab.
BRSCHNITT BRSCHNITT 32 mm M14

Testsieger

BRSCHNITT BRSCHNITT 32 mm M14
9.0/10about £15.79
View offer

What in this sample is aimed at porcelain

The M14 wax packs are the closest shape to a trade dry-porcelain bit. DT-DIATOOL at £24.99 is five 6 mm vacuum-brazed bits, sold for dry drilling. SHDIATOOL at £15.99 is two 6 mm M14 bits, with UK reviews of porcelain bathroom holes. BRSCHNITT at £15.79 is the 32 mm bit when the hole is a tap size. It is sold dry, and water is said to prolong life. Wet chuck saws can cut porcelain if you accept their rule. Meccion’s 22 mm saw states 500 to 800 rpm and water. Flintronic requires water, and a rim that burns without a spray is in the reviews. Those saws are diamond-coated. Vacuum brazing is not stated. Skip Zeeorymn when the tile is a 20 mm slab or a fixed porcelain floor you cannot spare. A long run or a larger hole fits a grinder you can control.

Dust and the fitted tile

Porcelain dust is still silica-bearing mineral dust. Wax inside a dry bit does not capture it. At work, HSE’s CIS36 sheet wants real suppression or M or H class extraction, and longer dry work also wants RPE at APF 20. A householder is not the COSHH dutyholder. Keep a vacuum at the hole, or use water where the listing and the tool allow it. Slurry that dries becomes dust again. Do not treat this method as permission to dry-cut a quartz slab. If the porcelain is already fixed, you have no offcut, and nothing supports the exit, ask a tiler. The same call applies when the only way to mount the bit is to take a grinder guard off.

Common questions

Can a carbide bit in the set drill the porcelain?
No. The carbide bit in the Zeeorymn set, and the masonry bit in the DKIBBITH set, are separate tools. Porcelain needs the diamond rim. Carbide is the ceramic spear, and even then it is the wrong choice once the tile is fully vitrified. Use the carbide or masonry piece only after the porcelain is already open, and keep hammer off while any glaze is still in the cut.
Is 20 mm the same job as a wall tile?
No. A thin porcelain wall tile and a 20 mm slab put different heat into the rim. Würth’s own dry M14 bit is aimed at about 15 mm, with a pause after that. Plan a pause, a coolant, and a spare. Do not copy a review of many holes on a thinner tile onto a slab.
Dry wax or water on porcelain?
Use the line on the listing. Wax-filled vacuum-brazed M14 bits are sold for dry porcelain and often last longer if you add water or pause. Meccion and Flintronic require water, and a dry run burns the coating. BGTEC allows dry use and says water gives a longer life. One dry BGTEC attempt on a porcelain slab buckled the body. Wax is not dust control in either case.
Why did a cheap set die after one hole?
Packs under about £11 draw that comment often, especially Zeeorymn and some ColumPRO and Flintronic reviews. The diamond layer on a coated or lightly bonded bit is thin, porcelain is hard, and pressure or a dry rim finishes it. A £5.99 set can be enough for one ceramic hole. It is a poor bet for a run of glazed porcelain. Replacing the bit is cheaper than forcing a polished rim.
When should a tiler take the fixed slab?
When the porcelain is already fixed, you have no offcut, and the back of the hole is unsupported. Also when the slab is thick, the bit you own has already failed one hole, or the cut would mean removing a grinder guard. The cost of a replacement slab is higher than the gap between a budget pack and a vacuum-brazed bit of the right diameter.

Related pages

Diamond drill buying guide

How to use a diamond drill

Best diamond drill

Diamond drill

Diamond drill bit: angle grinder or the drill chuck

Sources

Public UK sources from the research digest, last checked on 19 October 2026. Shelf prices and star lines are the amazon.co.uk figures in the display file.

  1. Topps Tiles: best drill bits for tiles (retrieved 19 October 2026)
  2. HSE CIS36: dust controls for drilling and coring (retrieved 19 October 2026)
  3. HSE CN8: diamond coring and slurry (retrieved 19 October 2026)
  4. ATS Diamond Tools: diamond drill bit types (retrieved 19 October 2026)
  5. Sigma UK: what size drill bit do I need (retrieved 19 October 2026)
  6. Würth UK: diamond dry core bit for tile, M14 (retrieved 19 October 2026)
  7. HSE: working with engineered stone (retrieved 19 October 2026)
  8. Tiling Supplies Direct: Rubi DRYGRES M14 bits (retrieved 19 October 2026)