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Cobalt drill bit set for stainless steel

Updated: October 2026

You are about to pay for a cobalt drill bit set for stainless steel, and the title already says the words you hoped to see. On the amazon.co.uk shelf captured on 15 October 2026, those words sit next to lists that skip 7.0 mm, a spec table that says HSS while the bullets say M35, and a brand field that says Generic. Read grade, then the enumerated sizes, then the point and the shank. Prices stay on the [stainless steel drill bit comparison](/hub/drilling-and-accessories/stainless-steel-drill-bit). Products Compared checked the ten listings against the printed sizes, with no lab test. A qualifying purchase can earn a commission at no extra cost to you.

You are about to pay for a cobalt drill bit set for stainless steel, and the title already says the words you hoped to see.

Our top picks

Bosch Bosch PRO HSS-Co set, 19 pieces, 1–10 mm

Best overall

Bosch Bosch PRO HSS-Co set, 19 pieces, 1–10 mm
8.4/10about £34.52
View offer
Bosch Bosch HSS PointTeQ 18-piece metal set

Alternative

Bosch Bosch HSS PointTeQ 18-piece metal set
5.6/10about £11.95
View offer
Rennie Tool Company Rennie Tools 5-piece cobalt set, 4–10 mm

Best value

Rennie Tool Company Rennie Tools 5-piece cobalt set, 4–10 mm
8.3/10about £13.99
View offer
On this page
  1. 1.What the listing must say
  2. 2.The size list is the product
  3. 3.Point, shank and the standard number
  4. 4.When the title and the spec table disagree

What the listing must say

For 304 or 316, look for M35 or HSS-Co, and for stainless among the named materials. A titanium nitride coat leaves the edge once you sharpen the bit. Cobalt in the steel remains after the colour is ground off. Grevosea B0HC72S5ZG, at £6.99, says M35 and prints Titanium in the finish field. Treat the coat as a second claim. PointTeQ, at £11.95 with 4.5 from 4,044 ratings, says HSS for metal and does not say stainless. Greywolf B0DZWRGDQQ at £60.79 says HSS-G, which Thürmer defines as ground after hardening, not M35. Bosch PRO says high speed steel with cobalt and names stainless, without a percentage. The full argument is on the cobalt versus HSS page.

The size list is the product

Read the enumerated diameters, then the title. Greywolf B0DZNQZK1V at £35.90, B0DZNTPX51 at £34.99 and the HSS-G set B0DZWRGDQQ say half-millimetre steps and omit 7.0 mm. Bosch PRO includes 7 mm and 7.5 mm, one of each size from 1 mm to 10 mm. The 10-piece set B0DQXQM5BM has 7 mm and no 6.5 mm. B0DQXRQD19, at £17.99, includes 3.3 mm, the usual M4 tap drill in CMT’s note, and stops at 6.5 mm. Rennie is 4, 5, 6, 8 and 10 mm at £13.99. Grevosea is 1/16 inch to 1/4 inch. Sheet thickness is on the sheet page.
Bosch Bosch PRO HSS-Co set, 19 pieces, 1–10 mm

Testsieger

Bosch Bosch PRO HSS-Co set, 19 pieces, 1–10 mm
8.4/10about £34.52
View offer

Point, shank and the standard number

BSSA recommends a 135° point for ordinary stainless. A split point is a separate phrase: Bosch PRO says “Centre Point” at 135°, not “split point”, while several M35 listings say 135° split point. KASAFE states 118°. DIN 338, BS 328 and ISO 235, as Dormer’s A777 sheet uses them, are jobber length, not a cobalt claim. Straight shanks suit a three-jaw chuck. Impact drivers are unstated on most of these twist sets.

When the title and the spec table disagree

Greywolf B0DZNTPX51 is titled as 19 pieces. The included-components field says six, the model is GWH9040-1, and the manufacturer part number is GWH9000A-1. PointTeQ is titled as 18 pieces, and “Number of Pieces” prints 1. Greywolf B0DQXRQD19 says 5% cobalt M35 in the bullets and high speed steel in the spec table. B0DQXQM5BM shows Generic in the brand field and Greywolf as manufacturer. The files do not resolve those clashes. Under the Consumer Rights Act 2015, goods should match the description you relied on. A six-piece line on a 19-piece title is a question for the seller, separate from a bit that work-hardened the steel. A star line is a record of buyers, not a hardness test. Life-multiplier sentences on several Greywolf listings stay unverified. Leave them out of the decision.

Common questions

Does “1–10 mm in 0.5 mm steps” always include 7 mm?
On this shelf it does not. Greywolf B0DZNQZK1V, B0DZNTPX51 and B0DZWRGDQQ omit 7.0 mm from the enumerated lists even though the titles talk about half-millimetre steps. Bosch PRO’s list includes 7 mm and 7.5 mm. Count the printed sizes. The phrase in the title is the claim you still have to verify.
What is the difference between a 135° point and a split point?
A 135° point is the angle BSSA prefers for ordinary stainless. A split point is a way of grinding that angle so it starts with less walking. Bosch PRO states 135° and the words “Centre Point”. Several M35 listings state “135° split point”. The KASAFE step bit states 118°. Match the phrase on the listing to the tool you think you are buying.
Does DIN 338 mean the bit is cobalt?
DIN 338, with BS 328 and ISO 235, is the jobber length pattern in Dormer’s data sheet. It describes the proportions of the bit. Cobalt is a material line: M35 or HSS-Co. You can meet both, or only the length standard, or only a cobalt claim with no standard number. Read them as two checks.
What if the brand field and the manufacturer field disagree?
Record both, and do not guess a third name. On B0DQXQM5BM the brand field says Generic and the manufacturer field says Greywolf. On B0DZNTPX51 the model number and the manufacturer part number differ, and the included-components line says six pieces against a 19-piece title. Ask the seller which description applies before you treat a short set as the one in the title.
When is a five-piece set enough, and when do you need the run to 10 mm?
Rennie’s five pieces, 4, 5, 6, 8 and 10 mm, are enough when those are the holes and you already have smaller pilots. You need the Bosch PRO run when the drawing includes 7 mm or the half sizes. The 13-piece Greywolf set stops at 6.5 mm. Job matches sit on the best-bits page.

Related pages

Stainless steel drill bits

Best drill bits for stainless steel: match the hole

Cobalt vs HSS drill bits: which side of this shelf

How to drill stainless steel: speeds, feed and oil

Drill bit for stainless steel sheet, step or twist

Sources

Public UK sources and the amazon.co.uk listings captured on 15 October 2026. The 8–12 m/min cutting-speed band is a rule of thumb, not a British standard.

  1. British Stainless Steel Association — Speeds and feeds for drilling and reaming stainless steels (retrieved 15 October 2026)
  2. Health and Safety Executive — PUWER overview (retrieved 15 October 2026)
  3. Health and Safety Executive — Using the right type of PPE (retrieved 15 October 2026)
  4. legislation.gov.uk — Consumer Rights Act 2015 (retrieved 15 October 2026)
  5. Armeg — Twister impact-rated HSS cobalt drill bits (retrieved 15 October 2026)
  6. Dormer Pramet A777 — jobber drill data sheet (BS 328, DIN 338, ISO 235) (retrieved 15 October 2026)
  7. David Harries — cobalt drill technical sheet (retrieved 15 October 2026)
  8. Thürmer Tools — drill FAQ (8–12 m/min is a rule of thumb, not a British standard) (retrieved 15 October 2026)