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How to use a step drill bit

Updated: 2026-10-23

The sheet spins, the cone squeals, and the hole is one step too large. That is avoidable if the work cannot move and you stop when the marked step breaks through. This is how to use a step drill bit on thin sheet, plastic or PVC, in rotary mode, with lubricant once the material is metal. The sequence uses UK workshop notes and the limits on the listings in our [step drill comparison](/hub/drilling-and-accessories/step-drill), updated 22 October 2026. We did not film a test. If the listing excludes the metal, use the [step drill bit buying guide](/hub/drilling-and-accessories/step-drill/sub/step-drill-buying-guide). A qualifying purchase can earn a commission at no extra cost to you.

The sheet spins, the cone squeals, and the hole is one step too large. That is avoidable if the work cannot move and you stop when the marked step breaks through.

Our top picks

YOKOCUT YOKOCUT 4–22 mm HSS 4241

Best overall

YOKOCUT YOKOCUT 4–22 mm HSS 4241
8.6/10about £5.12
View offer
YOKOCUT YOKOCUT 4–42 mm HSS 4241

Alternative

YOKOCUT YOKOCUT 4–42 mm HSS 4241
7.8/10about £8.93
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
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On this page
  1. 1.Set the drill and the sheet before you start
  2. 2.Speed and cutting fluid
  3. 3.Stop on the step, and what a bad sound means
  4. 4.Eyes, hands, and the hole behind the sheet

Set the drill and the sheet before you start

Mark the step before oil hides it. Reviewers of the ss shovan two-flute set use a pilot around 5 mm because the cone does not start cleanly. A fine pilot centred the YOKOCUT M2. Soft plastic may accept the point. Thin steel that can skate should not. Clamp the sheet and put scrap behind it. Do not hold the offcut by hand, or it will climb the cone. Keep rotary mode. DURI says drilling only, not hammer, and that warning belongs on every cone here. If you cannot clamp the sheet, do not start.

Speed and cutting fluid

There is no single rpm. RUKO’s manufacturer table puts hand-drill reaming of structural steel around 100–250 rpm past the first step. That is not a law. Ultimate Handyman stays nearer 3 mm, at a low speed, and treats WD-40 as penetrating oil rather than cutting oil. The listing wins: a 3 mm bullet, a 4 mm iron line and an 8 mm cap are not the same permission. Fluid does not make an excluded stainless listing into a stainless bit. Use cutting oil on the step that is cutting, and ease off as the hole grows. One review of the 4–42 mm bit calls those diameters the limit of a hand-held drill. If the drill bogs down, you are too fast, too dry or past the cap. The gauge is on the step drill for sheet metal page.
YOKOCUT YOKOCUT 4–22 mm HSS 4241

Testsieger

YOKOCUT YOKOCUT 4–22 mm HSS 4241
8.6/10about £5.12
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Stop on the step, and what a bad sound means

The cone keeps cutting into the next diameter if you stay on the trigger. Come off when the step you want has broken through. One extra feed turns a 20 mm gland hole into 22 mm. Pick the cone whose largest step is the size you need. A squeal means the edge is rubbing. Stop, add oil on metal, drop the speed and check you are square. A blue chip means the heat is already in the steel. Tips break when the drill is crooked or the sheet grabs. One YOKOCUT M2 review describes a bit that broke after a drop. If the piece is stuck where you cannot free it safely, call a competent person.

Eyes, hands, and the hole behind the sheet

Wear impact eye protection. HSE lists projectiles and metal splash as eye hazards. Its advice on bench drills is to avoid gloves because they catch. Follow that once the chuck is turning. Know what is behind the hole. A consumer unit, gas pipe, cable or unknown wall is not a practice cut. At work, PUWER means the drill is suitable, maintained and used by someone trained for it. If you are not that person, do not start. Asbestos is the same stop. HSE CN3 is silica control for concrete, and a cone is the wrong cutter for masonry. For a larger hole, or a panel that must stay free of swarf, see step drill vs hole saw.

Common questions

Do I need a pilot hole?
On thin steel, yes in practice. Buyers of the two-flute ss shovan set describe a pilot around 5 mm because the cone wanders, and a fine pilot is what centred the M2 cone. Soft plastic will sometimes accept the point on its own if you start square and slow. A pilot does not raise the thickness cap on the listing.
What speed do I use?
Slower as the step gets larger. RUKO’s manufacturer table puts hand-drill work on structural steel roughly in the 100–250 rpm band once you are reaming rather than starting. That is not a law, and it is not the speed for every plastic box. If the chip turns blue or the drill stalls, you are too fast or too dry for that step. Ultimate Handyman’s guide simply says a low speed on thin sheet.
Can I use WD-40?
Ultimate Handyman treats WD-40 as penetrating oil, not as a cutting lubricant. It is a weak stand-in on mild steel and a bad plan on stainless. Use a cutting oil or a paste made for metal, and keep it on the step that is actually cutting. Oil does not make a listing that says not for stainless into a stainless bit.
How do I stop at the right step?
Mark the diameter before you start, watch that mark, and release the trigger as soon as that step breaks through. Laser marks, where a listing has them, only help if you can still see them under oil. One extra step is a larger hole, not a rounder one. If the cone you picked does not include the size, change cone rather than pushing past the last step.
Can I use hammer mode?
No. DURI prints it, and it applies generally: these cones are for rotary drilling. Hammer mode is for masonry, and a step drill is the wrong cutter there. If the only drill you have is stuck in hammer, switch the mode before the bit touches the sheet.
When should I not do this myself?
Stop for a consumer unit, gas, structure, asbestos or an unknown wall, and for a snapped bit you cannot free without forcing the tool. At work, stop if you are not the person appointed to use that drill under PUWER. A thin aluminium cover on a bench, clamped, with eye protection, is the job this sequence is for. A live enclosure is not.

Related pages

Best step drill bit UK

Step drill

Step drill bit buying guide: hole, steel and shank

Step drill for sheet metal: thickness, grab and burrs

Step drill vs hole saw for thin sheet, plate or a box

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)