HSS drill bit or step drill
Updated: 2026-10-23
You are drilling a steel trunking lid, and the twist bit keeps grabbing as it breaks through. HSS drill bit or step drill is one decision, judged by sheet thickness. Prices are the amazon.co.uk lines in the [drill bit set comparison](/hub/drilling-and-accessories/drill-bit-set). Products Compared used those listings and UK trade pages, and did not run a lab test, on 21 October 2026. A qualifying purchase can earn a commission at no extra cost to you. Mixed shelf sets stay on the [drill bit set for wood, metal and masonry](/hub/drilling-and-accessories/drill-bit-set/sub/drill-bit-set-masonry-wood-metal).
You are drilling a steel trunking lid, and the twist bit keeps grabbing as it breaks through. HSS drill bit or step drill is one decision, judged by sheet thickness.
You are drilling a steel trunking lid, and the twist bit keeps grabbing as it breaks through. HSS drill bit or step drill is one decision, judged by sheet thickness. Prices are the amazon.co.uk lines in the drill bit set comparison. Products Compared used those listings and UK trade pages, and did not run a lab test, on 21 October 2026. A qualifying purchase can earn a commission at no extra cost to you. Mixed shelf sets stay on the drill bit set for wood, metal and masonry.
Our top picks
| Badge | Product | Set type | Steel or coating | Diameter range | Note | Price | Offer |
|---|---|---|---|---|---|---|---|
| Best overall |  Bosch Bosch PointTeQ 19-piece HSS | HSS twist set for metal | HSS, black oxide | 1–10 mm in 0.5 mm steps | 8.6 | about £14.12 | View offer |
| Alternative |  DelitonGude DelitonGude 5-piece step set | Step bits for sheet and plate | Title says HSS and titanium; material field says cobalt steel | 44 sizes across five pieces. Individual steps are not listed. | 5.7 | about £22.99 | View offer |
| Alternative |  LSLANSOON LSLANSOON 5-piece step set | Step bits for sheet metal | HSS, titanium coated | Cutting diameter 1.38 inches; minimum bore 0.25 inches. Step sizes are not listed. | 6.6 | about £12.99 | View offer |
On this page
What goes wrong with a twist bit in thin sheet
In sheet barely thicker than the point, the tip breaks through before the full diameter is cutting. The web grabs, the sheet climbs the bit, and the hole tears. Holding the sheet in your hand is how a grabbed bit becomes a cut. Cutting fluid helps the edge, and it does not change the geometry.
Ultimate Handyman puts the step drill on thin sheet, and you stop at the step you want. The matching mistake is a twist bit in sheet that is too thin. An 8 mm hole in 6 mm plate is already outside the step bit. How to run a twist bit without snapping it is the how to drill without snapping a bit page.
When the step bit is the right tool
Use a step bit when the sheet is within the thickness that bit is sold for, and when you want several hole sizes without swapping twist bits. Trunking, boxes, thin steel covers and plastic sheet are the usual jobs. You drill until the step you need is flush, and you stop. Enlarging an existing hole is the other job a twist bit does badly, because the old hole gives the tip nothing to centre on.
Cromwell specifies its HSS step drills for sheet up to about 3 mm (1/8 inch). That is Cromwell’s figure, not a law for every cone. The DelitonGude bullet only says the plate must be thinner than the step height, and that height is not printed. A titanium coat on HSS is still HSS. A safety-critical stainless hole, without HSSE or M35 on the listing, is a professional job.
When the HSS twist set is the right tool
Use a twist HSS set when you need one diameter in metal thicker than thin sheet, or a half-millimetre the step box never lists. The Bosch PointTeQ 19-piece is £14.12, 4.5 from 5,060 reviews: black-oxide HSS from 1.0 mm to 10.0 mm in 0.5 mm steps, for alloyed and mild steel, cast iron and plastic. It does not name masonry or stainless. The piece-count field says 1. It is the set for a 6 mm bracket or an 8 mm clearance hole, and the wrong tool for a trunking lid.
The Hurricane 230-piece at £41.69 reaches the same 10 mm ceiling with repeated small sizes, and it does not give you step geometry. Mixed X-Line metal bits stop at 5 mm or 6.5 mm.
What these two step listings actually say
The LSLANSOON set is £12.99, 4.0 from 199 reviews: five titanium-coated HSS step bits and a centre punch. The steps are not listed. A bullet says 118 degrees and the spec prints 1183 degrees. One UK review says a stainless worktop was drilled. Other reviews say the bits were dull. Treat the worktop line as one comment.
The DelitonGude set is £22.99, 4.3 from 46 reviews, and the written reviews are from Germany and France. They report early wear and a ruined bit in 10 mm angle. The title says high-speed steel and the material field says cobalt steel. Do not buy it as cobalt. Neither is the pick for a shelf in brick.
Common questions
Should I use a step bit or an HSS twist bit?
Use a step bit for thin sheet, trunking and enlarging a hole, if the sheet is within the thickness that bit states. Use an HSS twist bit for one precise size in thicker mild steel, such as the PointTeQ run from 1 mm to 10 mm. A twist bit in very thin sheet grabs. A step bit in thick plate rubs on the shoulder. The condition is thickness, not which box has more pieces.
How thick can a step drill go?
Cromwell states about 3 mm, which is 1/8 inch, for its HSS multi-diameter step drills. Würth states 3.5 mm for SMART STEP, a different bit, and some Faithfull bits are sold for up to 4 mm. DelitonGude does not print its step height. Treat about 3 mm as Cromwell’s figure, not a law.
Do I still need cutting fluid with a step bit?
Yes on steel. Low speed and lubrication are part of the step-bit method, not an optional extra for twist bits only. A dry step bit in sheet still heats the edge, especially if you push past the step you wanted. Fluid does not make thick plate a fair job for a step bit. Plastic may not want the same oil. Follow what the sheet actually is.
Is a titanium step bit a cobalt bit?
No. A titanium coat sits on HSS and wears away. Cobalt is in the steel, and the listing should say HSSE or M35 before you treat the bit as a stainless tool. LSLANSOON is titanium-coated HSS. DelitonGude’s title says high-speed steel and its material field says cobalt steel, so the cobalt word is not settled. A gold colour in the photo is not a third grade of steel.
Will a step bit drill stainless steel?
Do not plan on it with these two sets. One LSLANSOON review mentions a stainless worktop, and other reviews say the bits would not cut mild steel. That is not a general stainless result. DelitonGude leaves stainless unanswered, and its cobalt line conflicts with the HSS title. A safety-critical stainless hole wants a bit that clearly says HSSE or M35, cutting fluid, and someone who drills that metal often. These listings are not that bit.
Related pages
Sources
Public UK sources from the research digest, plus the ISO 5468 catalogue entry cited there. Shelf prices and star lines are the amazon.co.uk figures in the display file.
- HSE CN3, drilling with hand-held rotary tools (retrieved 22 October 2026)
- HSE, cutting and sanding wood (retrieved 22 October 2026)
- Consumer Rights Act 2015, section 9 (retrieved 22 October 2026)
- GOV.UK, General Product Safety Regulations 2005 (retrieved 22 October 2026)
- Bosch Professional GB, metal drill bits (retrieved 22 October 2026)
- Bosch Professional GB, TiN HSS twist bit (retrieved 22 October 2026)
- Cromwell, HSS step drills (retrieved 22 October 2026)
- ISO 5468:2017, carbide masonry bits (retrieved 22 October 2026)