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Step drill bit buying guide

Updated: 2026-10-23

A gold cone can shout 32 mm and titanium and still not tell you whether it enters your chuck, or whether the listing allows the steel. A step drill bit buying guide only helps if that check comes before the price. On the [step drill comparison](/hub/drilling-and-accessories/step-drill) the twelve amazon.co.uk listings run from about £3.79 to about £27.50. Use this order: largest hole, the thickness sentence, the steel grade, the shank, then the flute and the review count. The Products Compared editorial team took that order from those listings on 22 October 2026. Nothing here is a lab cut. A qualifying purchase can earn a commission at no extra cost to you.

A gold cone can shout 32 mm and titanium and still not tell you whether it enters your chuck, or whether the listing allows the steel. A step drill bit buying guide only helps if that check comes before the price.

Our top picks

YOKOCUT YOKOCUT M35 4–32 mm, 15 steps

Best overall

YOKOCUT YOKOCUT M35 4–32 mm, 15 steps
8.0/10about £27.50
View offer
YOKOCUT YOKOCUT 4–22 mm HSS 4241

Best value

YOKOCUT YOKOCUT 4–22 mm HSS 4241
8.6/10about £5.12
View offer
ss shovan ss shovan 3-piece, 2-flute

Rank 3

ss shovan ss shovan 3-piece, 2-flute
8.8/10about £11.99
View offer
On this page
  1. 1.Start with the largest hole and the thickness
  2. 2.Read the steel, not the colour
  3. 3.Make the shank fit the chuck you own
  4. 4.Ignore piece counts that are really steps

Start with the largest hole and the thickness

Write down the biggest finished hole you need, and look for that diameter as a marked step. The usual three-piece pattern is 4–12 mm, 4–20 mm and 4–32 mm. A single 4–22 mm cone is enough below that. QWORK runs from 1/8 in to 7/8 in, about 22 mm, so a metric gland is a conversion you do yourself. These listings do not share one thickness. DeWalt’s bullets say thin wall up to 3 mm. Several YOKOCUT HSS 4241 pages say within 4 mm on iron, copper and aluminium. The 4–42 mm YOKOCUT says within 3 mm. The ss shovan two-flute set says not thicker than 8 mm. QWORK’s stainless line is under 1 mm. The grade only matters inside that cap.

Read the steel, not the colour

Gold is a coating. Titanium or titanium nitride is not cobalt. HSS 4241 and HSS M2 pages that print an exclusion say they are not for stainless, glass, tile or walls, including a fully ground M2 cone with a 118° split point. M35 is the hotter-metal grade here: Rarapop at about £16.99, QWORK at about £20.99, and the YOKOCUT 4–32 mm cone at about £27.50. That title says 6% cobalt and the bullet says 5%. QWORK states 5% and limits stainless to under 1 mm. Rarapop names stainless and prints no millimetre cap. A missing cap is not permission to go thicker. Who each listing suits is on the best step drill bit UK page.
YOKOCUT YOKOCUT M35 4–32 mm, 15 steps

Testsieger

YOKOCUT YOKOCUT M35 4–32 mm, 15 steps
8.0/10about £27.50
View offer

Make the shank fit the chuck you own

A grade you like is useless if the chuck will not close. A 1/4 in hex (6.35 mm) is what xiluuyou, DURI, both ss shovan sets, Rarapop, DeWalt and QWORK state. The YOKOCUT 4–22 mm bit is an 8 mm tri-flat. It goes in a 10 mm chuck, not a hex-only holder. On the YOKOCUT listing titled 5–35 mm, UK reviewers say 9.5 mm is across the flats and the corners are over 10 mm, so it misses a 10 mm chuck and fits a 13 mm chuck. The 4–42 mm YOKOCUT uses the same 9.5 mm tri-flat. The M2 cone and the M35 YOKOCUT use a 10 mm tri-flat, which also wants 13 mm. If the chuck stops at 10 mm, leave those shanks.

Ignore piece counts that are really steps

Amazon’s pieces field sometimes counts steps, not cones. The YOKOCUT M2 is one 15-step bit and the pieces field says 15. The listing titled 5–35 mm shows three pieces on a single cone, and the cutting-diameter field says 32 mm. The 4–42 mm set name says Set of 4 while the included line is one bit. DeWalt DT5026-QZ clashes with itself. The Amazon title says 4–12 mm and the bullets say thin wall up to 3 mm, while the table says uncoated high carbon steel, a 4 cm bore and six pieces. DeWalt’s UK page titles the model 6–12 mm. BS 328-1 specifies twist drills, not step diameters. Two flutes are the ordinary cone. Four flutes are a different cut. A 5.0 from two reviews does not outrank 4.4 from 5,620. Speed and fluid are on how to use a step drill bit.

Common questions

Is a gold drill bit cobalt?
No. Gold on these listings is a titanium or titanium-nitride coat on high-speed steel. Cobalt, where it is claimed, is written as M35, sometimes with 5% or, on one title, 6%. If the grade code is missing, you have a coated HSS cone and a colour. Treat the coat as wear surface, not as the steel underneath.
Is HSS 4241, M2 or M35 the one for stainless?
HSS 4241 and HSS M2 pages that print an exclusion are not for stainless. M35 is the name on the Rarapop, QWORK and about £27.50 YOKOCUT rows. QWORK still limits stainless to under 1 mm, and the £27.50 reviews include both a galvanised plate and bits that died after one stainless hole.
Will this shank fit my drill?
A 1/4 in hex (6.35 mm) suits most cordless drills. An 8 mm tri-flat needs a chuck that opens to 8 mm. UK reviews on the 5–35 mm YOKOCUT say 9.5 mm across the flats misses a 10 mm chuck. A 10 mm tri-flat wants a 13 mm chuck. If the chuck will not close, the grade does not matter.
Why does the listing say three pieces when I can see one cone?
The pieces field is sometimes the step count, not the number of bits. A 15-step cone can be filed as 15 pieces. A set name can say four when the included line names one bit. Count the cones in the included-components line, and ignore a pieces field that matches the number of diameters printed on the cone.
When is a cheap set enough?
A cheap HSS hex cone is enough for plastic boxes and thin aluminium when the thickness line covers the sheet and the review count is more than a couple of lines. It is not enough when the page excludes stainless, when a 10 mm chuck meets a 9.5 mm shank, or when the only five-star line is two reviews.

Related pages

Step drill for sheet metal

Step drill vs hole saw

Step drill

Best step drill bit UK for plastic, steel or stainless

How to use a step drill bit on thin sheet and plastic

Sources

Public UK sources from the research digest, last checked on 22 October 2026. Shelf prices and star lines are the amazon.co.uk figures in the saved listings for this comparison.

  1. HSE, PUWER overview (retrieved 22 October 2026)
  2. HSE, PPE types (retrieved 22 October 2026)
  3. HSE CN3, silica and concrete drilling (retrieved 22 October 2026)
  4. Consumer Rights Act 2015, section 9 (retrieved 22 October 2026)
  5. GOV.UK, General Product Safety Regulations 2005 (retrieved 22 October 2026)
  6. BSI, BS 328-1 twist drills (retrieved 22 October 2026)
  7. DeWalt UK, DT5026-QZ (retrieved 22 October 2026)
  8. Ultimate Handyman, drilling metal (retrieved 22 October 2026)