A few holes in sheet or a bracket
You want a handful of metric holes and you will use oil in a slow gear. The five-piece Rennie set covers 4, 5, 6, 8 and 10 mm at about £13.99. It does not include anything under 4 mm.
Stainless steel drill bits compared (UK, 2026)
The best stainless steel drill bits, compared.
Top pick: Bosch PRO HSS-Co set, 19 pieces, 1–10 mm – Full 1–10 mm list in 0.5 mm steps, including 7 mm, at 4.6 from 5,129 ratings. Best value: Rennie Tools 5-piece cobalt set, 4–10 mm – Five M35 sizes at about £13.99, 4.4 from 207 ratings, if you will use oil. Updated October 2026.
Charlie White (Charlie DIYte)Expert source
You need a stainless steel drill bit when the hole is in stainless, not when the bit itself is stainless. On 304 and 316 the surface work-hardens if the edge rubs, so oil, feed and a sharp point sit beside the grade. The [stainless steel drill bit buying guide](/hub/drilling-and-accessories/stainless-steel-drill-bit/sub/stainless-steel-drill-bit-buying-guide) turns that into a checklist, separate from the prices below. Plain high-speed steel can still cut stainless when the bit stays sharp and you keep the feed up. The HSS set is sold for metal and does not say stainless.
You need a stainless steel drill bit when the hole is in stainless, not when the bit itself is stainless. On 304 and 316 the surface work-hardens if the edge rubs, so oil, feed and a sharp point sit beside the grade.
36 products checked · 62 hrs invested · +18,400 readers
10 of 10: Best stainless steel drill bits compared
Swipe for more
1-2 of 10Best overall
Best value
8.4/10
5.6/10
8.2/10
7.3/10
5.3/10
6.0/10
5.5/10
6.4/10
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1.7/10
∼ £35
∼ £12
∼ £14
∼ £8
∼ £61
∼ £35
∼ £18
∼ £36
∼ £18
∼ £7
4.6(5,129)
4.5(4,044)
4.4(207)
4.3(84)
4.3(68)
4.3(47)
4.3(17)
4.2(45)
3.9(24)
–
Personal buying guide
Which stainless steel drill bit fits the hole?
Question 1 of 2
What are you drilling?
The best stainless steel drill bits in detail
Our view
Across 50 United Kingdom reviews, this Bosch 19-piece set drilled a steel lintel, broken bolts and angle iron, and some stainless moved with oil and downward pressure. Model 2608587014 runs from 1 mm to 10 mm in 0.5 mm steps, including 7 mm and 7.5 mm, in a cassette at £34.52. The material line says high-speed steel with cobalt, and the percentage is not stated. The point is a 135° centre point rather than the words split point, on a cylinder shank. The listing score is 4.6 from 5,129 ratings. Other reviews left only small marks on stainless after two hours, found a factory burr that the buyer stoned off every bit, or chipped after a few holes in 2.0 mm galvanised steel, and one reviewer says to keep the bits away from moisture. If you want every half millimetre from 1 mm to 10 mm, this is the top pick in the set.
Pros
- Full run from 1 mm to 10 mm in 0.5 mm steps, including 7 mm
- 4.6 from 5,129 amazon.co.uk ratings
- UK reports of a steel lintel, broken bolts, angle iron and some stainless with oil
- One of each size in a cassette, model 2608587014
- Cylinder shank for a three-jaw chuck
Cons
- Cobalt percentage is not stated
- Point style is a 135° centre point, not the words split point
- Some UK reviews report little progress on stainless or a short life
- Factory burr on the edges in one review, and chipping after a few holes in 2.0 mm galvanised steel
Best for: A complete 1–10 mm metal set, including 7 mm, when you will use oil and can replace a bit that chips.
Less suitable: A buyer who needs a stated cobalt percentage, or a stainless job that has already marked the surface and stopped.
Specifications
- Model
- Bosch PRO HSS-Co set, 19 pieces, 1–10 mm
- Brand
- Bosch
- Price
- ∼£35
- Customer rating
- 4.6/5(5,129)
- Steel grade
- HSS-Co (% not stated)
- Point
- 135° centre point
- Split point
- No
- Size range
- 1–10 mm in 0.5 mm steps
- Bit type
- Twist set
- Pieces
- 19
- Shank
- Cylinder
- Case
- Cassette
- Stainless on listing
- Yes
Common questions
Does Bosch state the cobalt percentage?
No. The material line says high speed steel with cobalt. The title says the set is for stainless steel. The point style is “Centre Point” at 135°, not the words “split point”.
Are the half-millimetre sizes complete?
Yes in this listing. It includes 7 mm and 7.5 mm, unlike the Greywolf lists that skip 7.0 mm. There is one bit of each size from 1 mm to 10 mm.
Do the UK reviews agree on stainless steel?
No. The listing score is 4.6 from 5,129 ratings, and many of the 50 reviews in the saved listing describe lintels, mild steel and broken bolts. Some say stainless was straightforward with oil. Others report little progress, a short life, or a burr on the cutting edge.
Our view
UK reviewers cut mild steel, roofing sheet and galvanised steel with this Bosch 18-piece HSS set, and one buyer says it is not for stainless. The ToughBox set is £11.95, with a 135° self-centring tip and a round shank, and cobalt is not in the title or the bullets. The printed list runs from 1.0 mm to 10.0 mm, with 2.0 mm, 3.0 mm and 4.0 mm each twice, and without 6.5, 7.5, 8.5 or 9.5 mm. The spec field for the number of pieces prints 1 against the 18-piece title. The listing score is 4.5 from 4,044 ratings, and the indexed case is praised. Small bits snap in the reviews, a 5 mm bit shattered on first use and that reviewer says you need safety glasses, and two smaller bits would not cut out of the box. Country of origin on the listing is the United Kingdom and the warranty line is 1 year, but one relief-angle complaint had no reply after 18 days, so you should not treat this page as a stainless-steel set.
Pros
- 4.5 from 4,044 amazon.co.uk ratings at £11.95
- 135° self-centring PointTeQ tip in a ToughBox
- UK reports of mild steel, roofing sheet and galvanised steel
- Duplicate 2 mm, 3 mm and 4 mm bits, and 7 mm is in the list
- Country of origin on the listing is the United Kingdom
Cons
- Stainless steel and cobalt are not stated on this listing
- One UK buyer says the bits are not for stainless
- Small bits snap, including a 5 mm bit that shattered
- 6.5, 7.5, 8.5 and 9.5 mm are absent, and the piece-count field prints 1
Best for: Occasional DIY in mild steel, galvanised sheet and roofing sheet, when you already know this page does not sell the set as stainless.
Less suitable: Stainless steel, or a full half-millimetre set from 6.5 mm to 9.5 mm.
Specifications
- Model
- Bosch HSS PointTeQ 18-piece metal set
- Brand
- Bosch
- Price
- ∼£12
- Customer rating
- 4.5/5(4,044)
- Steel grade
- HSS
- Point
- 135° ground PointTeQ tip
- Split point
- No
- Size range
- 1–10 mm; extra 2–4 mm
- Bit type
- Twist set
- Pieces
- 18
- Shank
- Round
- Case
- ToughBox
Common questions
Is this set sold as a stainless-steel bit?
No. The title and bullets say HSS for metal, with a self-centring PointTeQ tip. Cobalt and stainless steel are not stated. The spec field “Number of Pieces” prints 1 against an 18-piece title.
Which sizes are duplicated?
2.0 mm, 3.0 mm and 4.0 mm appear twice. The printed list has no 6.5, 7.5, 8.5 or 9.5 mm bit. Country of origin on the listing is the United Kingdom.
What do UK reviewers say about stainless and breakage?
The listing score is 4.5 from 4,044 ratings. Reviews often praise sharp cutting in mild steel, roofing sheet and galvanised steel. One buyer says they are not for stainless. Others report small bits snapping or a 5 mm bit shattering, and one says two small bits would not cut out of the box.
Our view
Across 50 United Kingdom reviews, these five Rennie bits drilled stainless rod and sheet where ordinary HSS would not, usually with cutting oil or tapping lubricant and a slow speed. The case holds 4 mm, 5 mm, 6 mm, 8 mm and 10 mm at £13.99, and the bullets call them M35 cobalt with a precision-ground 135° split point for pillar drills, handheld electric drills and battery-powered drills. One report is about 30 holes in a 12 mm steel joist. The listing score is 4.4 from 207 ratings. Smaller bits snapped on countersunk hex bolts, a 5 mm bit snapped on first use in aluminium, and other reviews report blunting within minutes. One reviewer, after four small holes in 4 mm cast iron, claims the cobalt is plating rather than solid cobalt, which is not a test in the file. If you only need those five sizes and you will use oil, this is the best value in the set.
Pros
- 4.4 from 207 amazon.co.uk ratings at £13.99
- 4, 5, 6, 8 and 10 mm with a 135° split point
- UK reviews of stainless where ordinary HSS would not, with oil and a slow speed
- Listing names pillar drills, handheld drills and battery drills
- One report of about 30 holes in a 12 mm steel joist
Cons
- No bits below 4 mm and no half-millimetre sizes
- Smaller bits snapped on seized or countersunk fasteners
- One reviewer claims plating rather than solid cobalt, which is not a test in the file
- Case holes went too tight after the chuck raised a burr on the shank
Best for: Stainless and thick mild steel at 4, 5, 6, 8 or 10 mm, with cutting oil and a slow drill.
Less suitable: Seized bolts, sizes below 4 mm, or a full 1–10 mm set.
Specifications
- Model
- Rennie Tools 5-piece cobalt set, 4–10 mm
- Brand
- Rennie Tool Company
- Price
- ∼£14
- Customer rating
- 4.4/5(207)
- Steel grade
- M35 cobalt
- Point
- 135° split point
- Split point
- Yes
- Size range
- 4, 5, 6, 8, 10 mm
- Bit type
- Twist set
- Pieces
- 5
- Shank
- Straight
- Case
- Plastic case
- Stainless on listing
- Yes
Common questions
Which sizes are in the case?
4 mm, 5 mm, 6 mm, 8 mm and 10 mm. There is no 1 mm to 3 mm bit and no half-millimetre size in the listing.
Will the listing fit a cordless drill?
The listing says the bits suit pillar drills, handheld electric drills and battery-powered drills. It has a straight shank. It does not mention an impact driver or hammer action.
What do the UK reviews argue about?
Many of the 50 UK reviews say the bits drilled stainless or thick steel where ordinary HSS did not, often with oil and a slow speed. Others report snaps on seized bolts, fast blunting, or a case that would not accept a bit after the chuck marked the shank. One reviewer claims the cobalt is plating. The listing score is 4.4 from 207 ratings.
Our view
UK reviewers used this single KASAFE step bit to open a stainless hole from 10 mm to 13 mm and, in one report, to drill 14 holes of 13 mm in a 6 mm steel RSJ while the bit stayed sharp. It is one bit, not a twist set: 11 steps from 3 mm to 13 mm, a 118° split point, three spiral flutes and a 6.35 mm hex shank, at £7.99 with a plastic case. The bullets claim 5% cobalt and 66–69 HRC, and a thickness from 1 mm copper foil to 5 mm stainless plate. Those figures are listing claims. The page says the hex suits cordless drills, drill presses and impact drivers, and the listing score is 4.3 from 84 ratings, with 38 United Kingdom reviews. Other reviews report the edge going blunt after two holes or after three 5 mm holes in a milk churn, a tip that broke on first use, and step marks they did not trust. A hex shank snapped halfway along the shaft when it was not fully in the chuck, so you need the hex seated, and cutting oil is the reviewers' own method rather than a line in the listing.
Pros
- One bit covers 3 mm to 13 mm in 1 mm steps
- 6.35 mm hex shank named for cordless drills, drill presses and impact drivers
- UK reports of stainless sheet and a hole opened from 10 mm to 13 mm
- £7.99, with 4.3 from 84 ratings
- Millimetre marks on the steps and a plastic case
Cons
- Not a set of separate twist bits, and the point is 118° rather than 135°
- Edge went blunt after two holes, or after three 5 mm holes, in UK reviews
- Tip broke on first use for one reviewer, and step marks were disputed
- Hex shank snapped when it was not fully in the chuck
Best for: Enlarging holes in sheet and thin stainless, within the listing's 5 mm plate claim, with the hex fully in the chuck.
Less suitable: Deep holes, seized screws, or a job that needs a separate bit for each diameter.
Specifications
- Model
- KASAFE M35 step bit, 3–13 mm
- Brand
- KASAFE
- Price
- ∼£8
- Customer rating
- 4.3/5(84)
- Steel grade
- M35 (5% claimed)
- Point
- 118° split point
- Split point
- Yes
- Size range
- 3–13 mm, 11 steps
- Bit type
- Step bit
- Pieces
- 1
- Shank
- 1/4 inch hex
- Case
- Plastic case
- Stainless on listing
- Yes
Common questions
Is this a set of twist bits?
No. It is one step bit with 11 steps from 3 mm to 13 mm, a 118° split point and a 6.35 mm hex shank. The listing says it suits cordless drills, drill presses and impact drivers.
What thickness does the listing claim?
From 1 mm copper foil to 5 mm stainless plate. That is a listing claim. UK reviews include a 6 mm steel RSJ and also reports of the edge dying on thin stainless.
What breaks in the UK reviews?
Reviewers report a burnt or blunt edge, a tip that broke on first use, step marks they did not trust, and a hex shank that snapped when it was not fully in the chuck. Others report stainless sheet, a sink and an opened-out hole. The listing score is 4.3 from 84 ratings.
Our view
UK reviewers drilled a snapped bolt and a wheel locking nut with this Greywolf HSS-G set, and one says the first bit snapped and would not drill. It is the highest price here at £60.79, model GWH9085-1, with a black and gold oxide finish, a 135° self-centring multi-tip and two chip breakers, and it is not labelled M35. The title says 25 pieces from 1 mm to 13 mm in 0.5 mm steps, but the enumerated diameters omit 7.0 mm and leave 24 sizes, with a 3-flat shank stated from 5 mm. One bullet names stainless steel and high-temperature alloys, while another limits the examples to cast iron, copper, aluminium and other soft metals. The index box is praised, and another UK review calls the set a little expensive. A review body in the file describes a 19-piece 1–10 mm set, which does not match this listing. The amazon.co.uk score is 4.3 from 68 ratings, a line that says five times faster than ordinary drills is a listing claim rather than a test, and you should count the bits if 7 mm matters.
Pros
- Range extends to 13 mm, with a 3-flat shank from 5 mm
- 135° multi-tip and two chip breakers stated on the listing
- UK reports of a snapped bolt and a wheel locking nut
- Index box, and a listing score of 4.3 from 68 ratings
Cons
- £60.79, and the grade is HSS-G rather than a stated cobalt percentage
- Enumerated list omits 7.0 mm, leaving 24 sizes against a 25-piece title
- One UK review says the first bit snapped and would not drill
- One review describes a 19-piece 1–10 mm set that does not match this listing
Best for: Larger diameters up to 13 mm in sheet and general metal, if you check that 7 mm is actually in the box.
Less suitable: A buyer who wants a stated M35 or HSS-Co grade, or who expects 25 enumerated sizes for £60.79.
Specifications
- Model
- Greywolf 25-piece HSS-G turbine set, 1–13 mm
- Brand
- Greywolf
- Price
- ∼£61
- Customer rating
- 4.3/5(68)
- Steel grade
- HSS-G
- Point
- 135° multi-tip
- Size range
- 1–13 mm; no 7.0 mm
- Bit type
- Twist set
- Pieces
- 25 claimed
- Shank
- 3-flat from 5 mm
- Case
- Index box
- Stainless on listing
- Yes
Common questions
Is this a cobalt set?
The listing does not say M35 or a cobalt percentage. It says HSS-G with a black and gold oxide finish, a 135° self-centring tip and two chip breakers. One bullet names stainless steel; another names cast iron, copper, aluminium and other soft metals.
Does the size list match 25 pieces?
The bullet says 25 pieces from 1 mm to 13 mm in 0.5 mm steps. The enumerated diameters omit 7.0 mm, which leaves 24 sizes. The saved listing does not explain the gap.
What do UK reviews report?
UK reviews mention sharp bits, a useful case, and holes in snapped bolts. One says the first bit snapped and would not drill. Another review body describes a 19-piece 1–10 mm set, which does not match this listing. The score is 4.3 from 68 ratings.
Our view
UK reviews call this £34.99 Greywolf set sharp, including a high-tensile steel hole that still burnt the bits and a cast-iron cover that HSS only dimpled, and one review says they would not start on a normal screw head. The bullets say 5% cobalt and a 135° split point, with a straight shank and an uncoated finish. The model number GWH9040-1 does not match the manufacturer part number GWH9000A-1, the spec table prints 3 flutes, and the included-components field says 6 pieces while the title says 19. The enumerated sizes omit 7.0 mm. The plastic case is called not the best. The listing score is 4.3 from 47 ratings. Several reviews in the saved listing are from outside the United Kingdom, so you should not count those as UK opinion.
Pros
- Bullets state a 135° split point and 5% cobalt
- UK reports of a sharp cut, including a cast-iron cover after HSS only dimpled it
- One high-tensile steel hole was finished, though the bits burnt
- 4.3 from 47 ratings, at £34.99
Cons
- 7.0 mm is not in the enumerated list
- Included-components field says 6 pieces against a 19-piece title
- Model GWH9040-1 does not match part number GWH9000A-1, and the spec table says 3 flutes
- Would not start on a screw head in one UK review, and the case is called not the best
Best for: Heavy DIY in the listed half-millimetre sizes, if you check the box actually holds 19 bits.
Less suitable: A 7 mm hole, a screw head, or anyone who needs the model number and the piece count to agree.
Specifications
- Model
- Greywolf 19-piece M35 split-point set
- Brand
- Greywolf
- Price
- ∼£35
- Customer rating
- 4.3/5(47)
- Steel grade
- M35 (5% claimed)
- Point
- 135° split point
- Split point
- Yes
- Size range
- 1–10 mm; no 7.0 mm
- Bit type
- Twist set
- Pieces
- 19
- Shank
- Straight
- Case
- Index box
- Stainless on listing
- Yes
Common questions
Do the model numbers match?
No. The model number is GWH9040-1 and the manufacturer part number is GWH9000A-1. The included-components line says 6 pieces while the title says 19.
Is every half millimetre from 1 mm to 10 mm listed?
No. The printed list has 19 sizes and omits 7.0 mm. The spec table also says 3 flutes.
What do UK reviews say about hard steel?
One UK review says the bits burnt out on high-tensile steel but finished the hole. Another says they would not drill a screw head. Others report a sharp cut, including a cast-iron cover. The listing score is 4.3 from 47 ratings.
Our view
One of the two United Kingdom reviews says this 13-piece Greywolf set cut stainless sheet easily, and the other says it is only all right for light work. The sizes stop at 6.5 mm: 1.5, 2, 2.5, 3, 3.3, 3.5, 4, 4.2, 4.5, 5, 5.5, 6 and 6.5 mm, in a plastic index box at £17.99. There is no 8 mm or 10 mm bit. The bullets say fully ground 5% cobalt M35 and a hardness claim of 63 HRC, while the spec table says high-speed steel, and the saved listing does not resolve that. Split point is not stated, only a 135° tip. The listing score is 4.3 from 17 ratings. Neither of those two reviews reports a break, which is too small a sample for you to treat as a pattern.
Pros
- Includes 3.3 mm and 4.2 mm as well as half steps up to 6.5 mm
- Bullets claim 5% cobalt M35 and a 135° tip
- One UK review says the bits cut stainless sheet easily
- Plastic index box at £17.99
Cons
- Largest bit is 6.5 mm, so 8 mm and 10 mm are absent
- Spec table says HSS while the bullets say M35
- Only two UK reviews against 4.3 from 17 ratings
- Split point is not stated
Best for: Stainless sheet and other light work at 6.5 mm or under, including the 3.3 mm and 4.2 mm sizes.
Less suitable: Holes above 6.5 mm, or a buyer who wants more than two written UK reviews.
Specifications
- Model
- Greywolf 13-piece M35 set, 1.5–6.5 mm
- Brand
- Greywolf
- Price
- ∼£18
- Customer rating
- 4.3/5(17)
- Steel grade
- M35 (5% claimed)
- Point
- 135°
- Split point
- No
- Size range
- 1.5–6.5 mm
- Bit type
- Twist set
- Pieces
- 13
- Shank
- Straight
- Case
- Plastic index box
- Stainless on listing
- Yes
Common questions
How large is the biggest bit?
6.5 mm. The list is 1.5, 2, 2.5, 3, 3.3, 3.5, 4, 4.2, 4.5, 5, 5.5, 6 and 6.5 mm. There is no 8 mm or 10 mm bit.
Why do the material fields disagree?
The bullets say fully ground 5% cobalt M35. The spec table says High Speed Steel (HSS). The saved listing does not resolve that.
How many reviews are in the saved listing?
Two UK reviews, against a listing score of 4.3 from 17 ratings. One says the bits cut stainless sheet easily. The other says they are all right for light work.
Our view
UK reviewers put this 19-piece Greywolf set through steel and through a cast-iron cover that an HSS set only dimpled, and one buyer broke the 2 mm and 3 mm bits on first use in a drill press at low revs. The listing, model GWH9040R-1, says 5% cobalt, a 135° split point, a straight shank and an uncoated finish, with a hardness claim of 68 HRC. The title says 1–10 mm in 0.5 mm steps, but the enumerated list skips 7.0 mm and jumps from 6.5 mm to 7.5 mm. At £35.90 it sits close to the Bosch PRO set at £34.52, which does include 7 mm. The listing score is 4.2 from 45 ratings, and the plastic case is described as suitable for a van or garage. A rose-box line and a German-craftsmanship claim are not evidenced in the saved listing. If you need 7 mm, this list does not print it.
Pros
- 135° split point and a 5% cobalt claim on the bullets
- UK report of a cast-iron cover after an HSS set only dimpled it
- Most half-millimetre sizes from 1 mm to 10 mm are listed
- Plastic case described as suitable for a van or garage
Cons
- 7.0 mm is missing; the list jumps from 6.5 mm to 7.5 mm
- 2 mm and 3 mm bits broke on first use in a drill press at low revs
- £35.90, close to a full Bosch set, with 4.2 from 45 ratings
- 68 HRC is a listing claim, and the German-craftsmanship line is not evidenced
Best for: Half-millimetre metalwork up to 10 mm when you do not need a 7 mm bit and you will go slowly on 2 mm and 3 mm.
Less suitable: A 7.0 mm hole, or a drill-press job that loads the smallest bits on the first pass.
Specifications
- Model
- Greywolf 19-piece M35 set, 1–10 mm class
- Brand
- Greywolf
- Price
- ∼£36
- Customer rating
- 4.2/5(45)
- Steel grade
- M35 (5% claimed)
- Point
- 135° split point
- Split point
- Yes
- Size range
- 1–10 mm; no 7.0 mm
- Bit type
- Twist set
- Pieces
- 19
- Shank
- Straight
- Case
- Index box
- Stainless on listing
- Yes
Common questions
Is 7 mm in this 19-piece set?
The title says 1–10 mm in 0.5 mm steps. The enumerated list has 19 sizes and does not include 7.0 mm. It jumps from 6.5 mm to 7.5 mm.
What point does the listing specify?
A 135° split point, two flutes, a straight shank and an uncoated finish. The material line says cobalt steel and the bullets say 5% cobalt.
What do UK reviewers report about breakage?
UK reviews praise sharp edges and a cast-iron hole that an HSS set only dimpled. One reviewer says the 2 mm and 3 mm bits broke on first use in a drill press at low revs. The listing score is 4.2 from 45 ratings.
Our view
The Greywolf 10-piece set is sold for holes from 1 mm to 10 mm in whole millimetres, and the ten United Kingdom reviews split between a clean cut and a first-run failure. At £17.99 the listing calls the bits fully ground M35 with 5% cobalt, a 135° tip, a straight shank and a plastic index box, model GWH9010E. The hardness line is a listing claim of 63 HRC, not a measured result, and split point is not stated. The amazon.co.uk score is 3.9 from 24 ratings, the lowest star line in this set. Two reviews describe snapping or going blunt on the first run, and one says the bits are a poor choice for drilling out bolts and only worth trying on thin metal. One box arrived without the 2 mm bit, so you should count the sizes before you rely on the set.
Pros
- Whole-millimetre sizes from 1 mm to 10 mm, including 7 mm
- Listing says fully ground M35 with 5% cobalt and a 135° tip
- Plastic indexed box at £17.99
- Some of the 10 UK reviews say the bits stay sharp once they bite
Cons
- 3.9 from 24 ratings, the lowest star line in this set
- Two UK reviews report snapping or blunting on first use
- One box arrived without the 2 mm bit
- No half-millimetre sizes, and split point is not stated
Best for: Whole-millimetre holes from 1 mm to 10 mm in thin metal, if you count the bits on arrival and can return a set that snaps.
Less suitable: Drilling out bolts, or any job that needs half-millimetre sizes.
Specifications
- Model
- Greywolf 10-piece M35 set, 1–10 mm
- Brand
- Greywolf
- Price
- ∼£18
- Customer rating
- 3.9/5(24)
- Steel grade
- M35 (5% claimed)
- Point
- 135°
- Split point
- No
- Size range
- 1–10 mm in 1 mm steps
- Bit type
- Twist set
- Pieces
- 10
- Shank
- Straight
- Case
- Plastic index box
- Stainless on listing
- Yes
Common questions
Which diameters does this set list?
The listing lists ten bits: 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 mm. It does not list half-millimetre sizes. A plastic index box is included.
Does the listing say the bits are cobalt?
Yes. The bullets say fully ground M35 with 5% cobalt, a 135° tip and a hardness claim of 63 HRC. The brand field says Generic and the manufacturer field says Greywolf.
What failures show up in the UK reviews?
The saved listing has 10 UK reviews and a listing score of 3.9 from 24 ratings. Two reviews describe snapping or going blunt on first use, one says the 2 mm bit was missing, and one says they were poor for drilling out bolts.
Our view
No United Kingdom review in the saved listing says what this Grevosea set does in metal, so you only have the listing: 13 M35 jobber bits from 1/16 inch to 1/4 inch, about 1.6 mm to 6.35 mm, at £6.99. The bullets name a 135° split point, a titanium finish, a straight shank and an indexed case, and they include stainless steel among the materials. The page does not list each diameter in millimetres. The model number and the manufacturer part number do not match. There is no Customer Reviews line. A listing question about the titanium coating, and another about cordless drills, goes unanswered.
Pros
- £6.99 for 13 bits the listing calls M35 cobalt
- 135° split point and an indexed storage case
- Titanium finish named in the spec table
- Listing materials include stainless steel, cast iron, copper and aluminium
Cons
- No star rating and no UK review text in the saved listing
- Sizes are imperial, 1/16 inch to 1/4 inch, with no millimetre list
- Model number and manufacturer part number do not match
- Listing questions on the coating and on cordless drills are unanswered
Best for: A spare imperial set up to 1/4 inch when you accept that this page has no UK reviews.
Less suitable: Metric holes above 6.35 mm, or any buyer who wants a star rating before ordering.
Specifications
- Model
- Grevosea 13-piece M35 jobber set
- Brand
- Grevosea
- Price
- ∼£7
- Steel grade
- M35 cobalt
- Point
- 135° split point
- Split point
- Yes
- Size range
- 1/16–1/4 inch
- Bit type
- Twist set
- Pieces
- 13
- Shank
- Straight
- Case
- Indexed storage case
- Stainless on listing
- Yes
Common questions
Are the sizes metric?
The listing gives the range as 1/16 inch to 1/4 inch, thirteen bits. It does not list each diameter in millimetres.
Is there a UK star rating in the saved listing?
No. There is no Customer Reviews line and no review text. Price on the listing is £6.99.
What finish does the spec table give?
Titanium. The bullets call the bits M35 cobalt with a 135° split point. A listing question asks about the coating and about cordless drills, and the saved listing does not answer either.
How we compared
We compared ten amazon.co.uk listings for drilling stainless, taken from a wider shelf of twist sets and one step bit, using the pages captured on 15 October 2026. The order follows the grade, the printed sizes, the point, the shank and the UK review record. This is not a lab test, and a star rating is not a measured life.
1
Steel grade
30%For 304 or 316, prefer a listing that says M35 or HSS-Co. HSS-G is not cobalt. A gold finish is not a grade, and a hardness figure on the bullet is a seller claim.
2
Printed sizes
25%The enumerated diameters matter more than the title. A 0.5 mm claim can omit 7.0 mm, duplicate small sizes, or stop at 6.5 mm.
3
Point
15%About 135° suits ordinary stainless. About 120° is the association figure for free-machining 303. A split point is separate from the angle.
4
Bit type and thickness
15%A twist bit is one diameter. The only step bit here is 3–13 mm for sheet. Large twist bits snatch in thin sheet. A step bit is wrong for deep bar.
5
Shank and listing evidence
15%A straight or cylinder shank suits a chuck. Piece-count fields sometimes disagree with the title. Stars and review counts are amazon.co.uk figures, not a lab score.
Independent review
Last updated: October 2026
8 sources checked
Stainless steel drill bit buying guide
Choose the bit for the stainless you are drilling, then check the printed sizes and the thickness. M35 or HSS-Co is the usual grade for 304 and 316. Plain HSS can still cut if you keep the feed up. A step bit is for sheet. A twist set is for one diameter at a time. Prices below are the amazon.co.uk figures from 15 October 2026.
What is a stainless steel drill bit?
A stainless steel drill bit is a bit for drilling stainless, not a bit made of stainless. You choose plain high-speed steel, cobalt high-speed steel (often sold as M35, about 5%), or a step bit when the job is sheet. The British Stainless Steel Association notes that 304 (1.4301) and 316 (1.4401) work-harden if the bit rubs, so the edge, the oil, the feed and the speed matter as much as the name on the box.
Best for
- Holes in 304 or 316 when you will use oil and a slow feed
- A full 1–10 mm metal set that actually lists 7 mm
- Thin stainless sheet, where a step bit is the closer match
Not ideal for
- Hammer or SDS drilling
- A deep hole in 316 or duplex, or a reamed hole
- Anyone who needs a stated M42 grade, which is not on this shelf
Mistakes to avoid
- 1
Mild-steel speed on 304 or 316
Running at a speed that suits mild steel, or dwelling until the spot shines, work-hardens 304 and 316. Keep feeding, use oil, and look for a chip. On a cordless drill, use the low gear.
- 2
Buying on stars or the highest price
The largest review count on this page is not automatically the cobalt set, and the highest price is HSS-G, not M35. Read the grade and the printed sizes. A 0.5 mm title can still omit 7.0 mm.
- 3
Hammer mode, or a step bit in bar
These listings are for rotary drilling. Hammer or SDS action is the wrong mode. A step bit is for sheet and for opening a hole. It is the wrong tool for a deep hole in bar.
What to weigh up
Steel grade
HighSteel grade is the first check for 304 and 316. Prefer a listing that says M35 or HSS-Co. A gold finish is not a grade: [cobalt or a gold coating](/hub/drilling-and-accessories/blog/cobalt-or-a-gold-coating) separates the alloy from the colour on the flute. M35 is often sold as about 5% cobalt. Several Greywolf bullets state 5%, and that figure is a listing claim, not an assay. The Bosch PRO line says high-speed steel with cobalt and does not give a percentage.
Printed sizes
HighPrinted sizes decide whether the box matches the hole. Read the enumerated list, not the title. Three Greywolf listings that advertise 0.5 mm steps omit 7.0 mm and jump from 6.5 mm to 7.5 mm. The HSS-G title says 25 pieces from 1 mm to 13 mm, and the enumerated diameters also omit 7.0 mm, which leaves 24 sizes. The Bosch PRO set includes 7 mm and 7.5 mm, one bit of each size from 1 mm to 10 mm. The Bosch HSS PointTeQ set duplicates 2 mm, 3 mm and 4 mm and leaves out 6.5, 7.5, 8.5 and 9.5 mm.
Which option suits you?
Three typical situations, each with a recommendation from this comparison.
Plain HSS has already burnt
Ordinary HSS has dulled or stalled, and you want HSS-Co with every half millimetre from 1 mm to 10 mm, including 7 mm. The Bosch PRO set is the top pick for that list. The cobalt percentage is still unstated.
Thin stainless or a sink
The hole is in sheet, or you are opening an existing hole, and a large twist bit would snatch. The KASAFE step bit runs from 3 mm to 13 mm. Seat the hex fully in the chuck. It is the wrong tool for deep bar.
Common questions about stainless steel drill bits
Which stainless steel drill bit is the top pick for 2026?
The top pick on this page is the Bosch PRO 19-piece HSS-Co set, model 2608587014, at about £34.52. The printed sizes run from 1 mm to 10 mm in 0.5 mm steps, including 7 mm, on a cylinder shank. The listing shows 4.6 from 5,129 amazon.co.uk ratings. Cobalt percentage is not stated, and the point is a 135° centre point. Some UK reviews report little progress on stainless. This is a listing comparison, not a lab test.
How much does a stainless steel drill bit cost?
On these ten listings, captured on 15 October 2026, prices run from about £6.99 to about £60.79. Under about £15: Grevosea with no star line, the KASAFE step bit at about £7.99, Bosch HSS PointTeQ at about £11.95, and Rennie at about £13.99. Near £35 you will see the Bosch PRO set and two Greywolf 19-piece sets. The set at about £60.79 is HSS-G, not M35.
What should I check before I buy a stainless steel drill bit?
Check the grade first. For 304 or 316, prefer a listing that says M35 or HSS-Co. HSS-G is not cobalt. The usual point is about 135° for ordinary stainless, and a split point is separate from the angle. Read the printed diameters, because a 0.5 mm title can omit 7.0 mm. Use a twist bit for one diameter and the 3–13 mm step bit for sheet. Stars are not a lab score.
Can ordinary HSS drill stainless steel?
Yes, with a limit. The British Stainless Steel Association says a sharp, short high-speed steel bit can drill stainless if you keep the feed up and do not dwell. The Bosch HSS PointTeQ set on this page is sold for metal and does not say stainless. If plain HSS has already burnt, compare an HSS-Co or M35 listing. Use oil, a slow gear, and look for a chip rather than dust.
Why do some sets miss the 7 mm bit?
The title can say 1–10 mm in 0.5 mm steps while the list jumps from 6.5 mm to 7.5 mm. That gap is on two Greywolf 19-piece listings, and the HSS-G list that claims 25 pieces also omits 7.0 mm. The Bosch PRO listing includes 7 mm and 7.5 mm. A missing size can be a description problem under the Consumer Rights Act 2015, so count the bits on arrival.
Should I use a step bit or a twist bit on stainless sheet?
Use a step bit for thin sheet, and a twist bit for one diameter in thicker material. The only step bit here is the KASAFE, 11 steps from 3 mm to 13 mm, with a 1/4 inch hex shank, at about £7.99. The listing claims foil up to 5 mm plate. UK reviews include clean sheet holes and burnt edges. Seat the hex fully and use oil. A step bit is the wrong tool for deep bar.
What speed and safety points apply in the UK?
Armeg's free-cutting stainless column is about 1,070 rpm at 3 mm and 530 rpm at 6 mm. Another UK chart prints 849 rpm at 6 mm. An 8–12 m/min band is a rule of thumb, not a British standard. On a cordless drill, use low gear and look for a chip. Use eye protection. Gloves that can catch are a poor choice on a bench drill. For a spot weld, use a spot weld drill rather than a jobber bit.
Our verdict
The top pick is the Bosch PRO 19-piece HSS-Co set when you want every half millimetre from 1 mm to 10 mm, including 7 mm, at about £34.52. The cobalt percentage is not stated, and some UK reviews still report slow progress on stainless. The best value is the Rennie Tools five-piece M35 set at about £13.99 if 4, 5, 6, 8 and 10 mm are enough and you will use oil at a slow speed. For thin sheet, the KASAFE step bit is the closer match. Plain HSS can drill stainless if you keep the feed up, but the Bosch HSS PointTeQ listing does not say stainless.
Best overallView offer
Bosch PRO HSS-Co set, 19 pieces, 1–10 mm
Full 1–10 mm list in 0.5 mm steps, including 7 mm, at 4.6 from 5,129 ratings.
Best value
View offer
Rennie Tools 5-piece cobalt set, 4–10 mm
Five M35 sizes at about £13.99, 4.4 from 207 ratings, if you will use oil.
Editorial
Editor
Drill bitsStainless steelDIY tools
Products Compared publishes British-English buying guides based on amazon.co.uk listings and public UK sources. We do not run a lab and we do not invent test scores.
Updated: October 2026
8 sources checked
Guides to stainless steel drill bits
Guides on what to look for, how to use a product, and common mistakes.
Best stainless steel drill bit by jobWhich type fits a bracket, a sheet hole or a full 1–10 mm list.Stainless steel drill bit buying guideGrade, point, printed sizes and shank, without the price table.Cobalt versus HSSWhen M35 or HSS-Co is the better fork, and when plain HSS still cuts.How to drill stainless steelFeed, speed and work hardening, without the product table.Drilling stainless sheetStep bit versus twist bit when the metal is thin.
Related comparisons
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.
- British Stainless Steel Association — Speeds and feeds for drilling and reaming stainless steels (retrieved 15 October 2026)
- Health and Safety Executive — PUWER overview (retrieved 15 October 2026)
- Health and Safety Executive — Using the right type of PPE (retrieved 15 October 2026)
- legislation.gov.uk — Consumer Rights Act 2015 (retrieved 15 October 2026)
- Armeg — Twister impact-rated HSS cobalt drill bits (retrieved 15 October 2026)
- Dormer Pramet A777 — jobber drill data sheet (BS 328, DIN 338, ISO 235) (retrieved 15 October 2026)
- David Harries — cobalt drill technical sheet (retrieved 15 October 2026)
- Thürmer Tools — drill FAQ (8–12 m/min is a rule of thumb, not a British standard) (retrieved 15 October 2026)
Expert source (DIY & tools): Charlie White (Charlie DIYte) (external profile) – public expert commentary used as a research source, not as a contributor to our pages.
This page contains affiliate links to amazon.co.uk. If you buy through them, we may earn a commission at no extra cost to you. Prices and star ratings come from the listings compared here. We did not run a lab test.