Bi-metal vs carbide hole saw
Updated: 2026-10-23
You need a round hole in thin metal, or in timber that still has nails in it, and the listings all say carbide as if that were one tooth. It is not. A bi-metal vs carbide hole saw choice starts with the materials line, because a carbide set for plasterboard will not do the job of a carbide set for stainless, and carbon steel is a third path. The full price table stays on the [hole saw set comparison](/hub/drilling-and-accessories/hole-saw-set). Products Compared used the amazon.co.uk listings checked on 19 October 2026 and did not run a lab test. A qualifying purchase can earn a commission.
You need a round hole in thin metal, or in timber that still has nails in it, and the listings all say carbide as if that were one tooth. It is not.
You need a round hole in thin metal, or in timber that still has nails in it, and the listings all say carbide as if that were one tooth. It is not. A bi-metal vs carbide hole saw choice starts with the materials line, because a carbide set for plasterboard will not do the job of a carbide set for stainless, and carbon steel is a third path. The full price table stays on the hole saw set comparison. Products Compared used the amazon.co.uk listings checked on 19 October 2026 and did not run a lab test. A qualifying purchase can earn a commission.
Our top picks
| Badge | Product | Tooth | Sizes | Metal on the listing | Note | Price | Offer |
|---|---|---|---|---|---|---|---|
| Best overall |  TOOLMAYS TOOLMAYS carbide set, 54–105 mm | Carbide | 54, 57, 65, 76, 92, 105 mm | Not for metal | 7.0 | about £69.99 | View offer |
 HYCHIKA HYCHIKA bi-metal set, 19–68 mm | Bi-metal | 19–68 mm | Soft metal, not stainless | 9.2 | about £19.99 | View offer | |
| Alternative |  Mollom Mollom TCT set, 16–54 mm | TCT | 16–54 mm | Stainless named | 7.3 | about £59.39 | View offer |
On this page
Three teeth, not two
Carbon steel is the cheap cup for soft sheet, often to 127 mm or 152 mm, and the honest listings say wood, plasterboard and thin plastic, or not metal. Bi-metal is high-speed steel teeth, sometimes M42 with about 8% cobalt, for wood, plastic and thin metal. Carbide, often called TCT, is the brittle tooth for a listing that names stainless or nails, if you can keep the speed down.
On a softwood cable hole, carbide is extra money and chips if you chatter. On thin mild steel, bi-metal with fluid is the usual default. A toothed cup here does not cut tile, glass, brick or concrete. If you have not picked a diameter yet, use the hole saw set buying guide.
Bi-metal, including M42
Choose bi-metal when the listing names thin mild steel or aluminium as well as wood and plastic. HYCHIKA bi-metal names soft metal, wood, PVC, plastic and gypsum board, states 40 mm, and does not name stainless. That is the mixed default here, not a stainless kit. Amazon Basics names mild steel, aluminium, plastic and plasterboard on HSS-M3 cups from 20 mm to 68 mm, then the compatible-material field says plastic only. Reviews include fast wear on metal.
M42 is still bi-metal. BULLITT prints M42 with 8% cobalt, a hex shank, and a 1.6 mm sheet limit in mild steel, stainless and aluminium, at 20, 25 and 32 mm only. The spec field says high speed steel. UK reviews split: some thin-metal cuts succeed, one new 20 mm cutter did not cut stainless, and the ejector spring is a repeated complaint. Moendergo’s title says cobalt, the precision bullet says high-speed steel, and the spec says alloy steel. That clash is not an M42 proof. How slow, and when to add fluid, is how to use a hole saw.
Two carbide listings that do not swap
Mollom is the TCT set that names stainless. Ten cups from 16 mm to 54 mm, titanium-plated tungsten carbide, £59.39, 4.3 from 3,360 reviews. The bullets include stainless plate, hard metal, iron, mild steel, alloy steel, aluminium, FRP and plastic, and they exclude tile, glass, concrete and stone. No cutting depth and no case are named. Reviews go both ways: teeth off the cup after one thin sheet, and clean cuts when the speed stays low and fluid is used. There is no life multiple on this listing.
TOOLMAYS is the other carbide set, and it is not a stainless cutter. Six cups from 54 mm to 105 mm, £69.99, 25 mm per pass, for timber and plasterboard, with nails, screws and staples named. The same bullet says not for metal or ceramic tile. The star line is 5.0 from 3 reviews, all marked Canada. A plasterboard hole with a screw in the way is this listing. A stainless knockout inside 54 mm is Mollom. Swapping the boxes because both say carbide blunts the wrong tooth.
What carbon still is
Carbon steel still wins for soft wood, plasterboard or thin plastic when you want 102 mm or 152 mm without carbide money. HYCHIKA carbon runs from 19 mm to 152 mm, states 25 mm, says not hard board, and is 4.4 from 7,282 reviews. Oudtinz runs to 127 mm and says not metal. Gunpla runs to 152 mm and allows aluminium sheet with water or oil. A 4.6 there is not a stainless score.
Flintronic says high-speed carbon steel and heat-treated M42 in the same bullets. Treat that as unresolved. Ribowri is twin blades from 40 mm to 200 mm for plasterboard, with no review line. It is not carbide and not a metal kit. Concrete and ceramic tile are outside this category.
Common questions
When is bi-metal the right tooth?
When the listing names thin mild steel or aluminium with wood and plastic, and you will use fluid and a low speed on the metal. HYCHIKA bi-metal names soft metal, not stainless, and states 40 mm. It is the wrong tooth for nails if another listing is the one that names them.
When does the listing need to say carbide or TCT?
When the hole is in stainless, or in wood with nails, screws or staples, and that sentence is on the same page as the cups. Mollom names stainless and stops at 54 mm. TOOLMAYS names nails and excludes metal.
Why are there two carbide sets that cut different materials?
Carbide is a tip, not a duty. Mollom names stainless and excludes tile and concrete. TOOLMAYS names nails and excludes metal and ceramic tile. They do not substitute.
Where does carbon steel still win?
On soft wood, plasterboard and thin plastic, especially at 102 mm or 152 mm, if you will not touch steel. HYCHIKA carbon also excludes hard board. Carbon loses on mild steel plate and stainless.
What does M42 or 8% cobalt add inside bi-metal?
On BULLITT it is the stated alloy for three hex-shank cups, with a 1.6 mm sheet limit in mild steel, stainless and aluminium. UK reviews still include a failed stainless cut and springs that leave the cup. Do not import that 8% onto Moendergo.
Can I use these toothed cups on tile or brick?
No. Mollom excludes tile, glass, concrete and stone. TOOLMAYS excludes ceramic tile. A toothed hole saw is the wrong family for masonry and glazed tile.
Why do carbide teeth snap off in reviews?
They are hard and brittle. Mollom reviews include teeth leaving the cup after one thin sheet, and cleaner cuts when speed stays low and fluid is used. Chatter and hammer mode do the damage. That is not a measured life in holes.
Related pages
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 checked on 19 October 2026.
- HSE: PUWER overview (retrieved 19 October 2026)
- HSE: wood dust (retrieved 19 October 2026)
- RS: hole saws guide (retrieved 19 October 2026)
- RS PRO bi-metal hole saw datasheet (retrieved 19 October 2026)
- Starrett UK: bi-metal speeds (retrieved 19 October 2026)
- Approved Document P (2013) (retrieved 19 October 2026)
- LightHub: downlight cut-out sizes (retrieved 19 October 2026)
- Electrical Safety First: drills (retrieved 19 October 2026)