Ratings represent our editorial opinion, not Amazon's. LumberMensHomes is reader-supported and may earn an affiliate commission. Details

Best Drill Bit For 8mm Steel

Tom Woodward

Senior reporter

★★★★★5.0

500+ views

Today

6 min read

Looking for the best drill bit for 8mm steel in March 2026? We reviewed 8 popular options from brands like 8mm, Cobalt, PATIKIL, Metric, uxcell, MewuDecor, HLOFIZI and compared them on the things that matter most: build quality, comfort, ease of use, durability, and overall value. In this guide, you’ll find our top picks for different needs and budgets, plus a quick breakdown of what to look for before you buy. If you want a drill bit for 8mm steel that performs well and holds up over time, this shortlist will help you choose with confidence.

Our Top Picks

Best Overall

8mm Metric M35 Cobalt Steel Extremely Heat Resistant Twist Drill Bit of 1pcs with Straight Shank to Cut Through Hard Metals Such as Stainless Steel and Cast Iron, 5% Cobalt M35 Grade HSS-CO

★★★★★★4.8

Material Grade:M35 Cobalt Steel

Coating Type:Titanium Coating

Point Angle:118° Split Point

Flute Geometry:2 Flutes

Shank Design:Straight Shank

Maximum RPM:Up to 6000 RPM

Titanium‑coated 8mm M35 cobalt drill cuts stainless steel and cast iron fast, with long life and precise chip evacuation.

Check Price

Best Value

8mm Straight Shank Drill Bits 2pcs 4341 High-Speed Stee Black and Gold Finish for Copper Stainless Steel Alloy Metal Wood Plastic

★★★★★★4.6

Material Grade:4341 High Speed Steel

Coating Type:Gold‑Titanium & Black Nitride

Point Angle:118° Split Point

Flute Geometry:2 Flutes

Shank Design:Straight Shank

Maximum RPM:Up to 5500 RPM

Dual‑coated 8mm HSS bits drill copper, stainless steel and plastics efficiently, offering solid performance at an affordable price.

Check Price

Best Premium

Cobalt Drill Bit Set 8mm - 10pcs, M35 Twist Drill Bits Straight Shank, 8mm High Speed Steel Drill Bits for Drilling in Hard Metal, Stainless Steel, Cast Iron

★★★★★★4.8

Material Grade:M35 Cobalt Steel

Coating Type:Gold Oxide Coating

Point Angle:145° Split Point

Flute Geometry:2 Flutes

Shank Design:Straight Shank

Maximum RPM:Up to 6200 RPM

Gold‑oxide 8mm M35 cobalt set delivers ultra‑hard drilling, precise 145° start, and 10‑piece case for industrial tough metals.

Check Price

Detailed Reviews

What to Look For Drill Bit For 8mm Steel

Material Grade

Determines hardness and wear resistance; cobalt‑M35 (5% Co) outperforms standard HSS, providing longer life and faster cutting in steel up to HRC 38.

Coating Type

Reduces friction and heat build‑up; titanium (TiN) coating extends bit life, improves chip evacuation, and keeps the cutting edge sharper longer.

Point Angle

A 135° tip concentrates cutting forces for accurate entry in hard metals, minimizing walk‑off and delivering a clean, round hole in 8 mm steel.

Flute Geometry

Two‑flute, staggered cutting teeth promote efficient chip removal and lower heat, crucial for maintaining stability when drilling stainless steel or cast iron.

Shank Design

Straight, non‑tapered shank fits standard chucks and collets, ensuring firm grip, precise centering, and reduced vibration during high‑speed drilling.

Maximum RPM

Specifies the highest safe spindle speed; lower RPM (≈ 2,500 rpm for 8 mm steel) limits heat, preventing premature dulling of the cutting edge.

by 8mm

X Score

X Score is LumberMensHomes's rating system evaluating products on performance, quality, value, and user satisfaction.

★★★★★

4.8 / 5.0

8mm Metric M35 Cobalt Steel Extremely Heat Resistant Twist Drill Bit of 1pcs with Straight Shank to Cut Through Hard Metals Such as Stainless Steel and Cast Iron, 5% Cobalt M35 Grade HSS-CO

BEST OVERALL

Designed for demanding metalwork, this 8mm M35 cobalt drill offers exceptional hardness and heat resistance. The titanium coating reduces wear while the 2‑flute geometry clears chips efficiently. A 118° split point starts accurately, and the straight shank fits standard chucks. It sustains high speeds up to 6000 RPM, delivering fast, clean holes in stainless steel and cast iron with reliable precision.

Key Specifications

Material Grade

✓M35 Cobalt Steel

Coating Type

✓Titanium Coating

Point Angle

✓118° Split Point

Flute Geometry

✓2 Flutes

Shank Design

✓Straight Shank

Maximum RPM

✓Up to 6000 RPM

Reasons to Buy

✓Long tool life
✓Fast cutting speed
✓Excellent chip evacuation
✓Stable straight shank

Reasons Not to Buy

✗Single piece packaging
✗Higher price than basic HSS

Check Price

by 8mm

X Score

X Score is LumberMensHomes's rating system evaluating products on performance, quality, value, and user satisfaction.

★★★★★

4.6 / 5.0

8mm Straight Shank Drill Bits 2pcs 4341 High-Speed Stee Black and Gold Finish for Copper Stainless Steel Alloy Metal Wood Plastic

BEST VALUE

The 4341 high‑speed steel pair delivers solid performance on copper, stainless steel and plastics. A dual gold‑titanium and black nitride finish boosts wear resistance, while the 2‑flute design removes debris quickly. The 8mm straight shank fits all chucks, and the bits handle speeds up to 5500 RPM, offering reliable drilling at an affordable price for hobbyist and professional use today everywhere.

Key Specifications

Material Grade

✓4341 High Speed Steel

Coating Type

✓Gold‑Titanium & Black Nitride

Point Angle

✓118° Split Point

Flute Geometry

✓2 Flutes

Shank Design

✓Straight Shank

Maximum RPM

✓Up to 5500 RPM

Reasons to Buy

✓Dual protective coating
✓Good chip clearance
✓Fits standard chucks
✓Cost effective

Reasons Not to Buy

✗Limited to two pieces
✗Not ideal for hardened steel

Check Price

by Cobalt

X Score

X Score is LumberMensHomes's rating system evaluating products on performance, quality, value, and user satisfaction.

★★★★★

4.8 / 5.0

Cobalt Drill Bit Set 8mm - 10pcs, M35 Twist Drill Bits Straight Shank, 8mm High Speed Steel Drill Bits for Drilling in Hard Metal, Stainless Steel, Cast Iron

BEST PREMIUM

This 10‑piece 8mm M35 cobalt set combines high hardness with a gold oxide coating for extended life. The 145° split point starts precisely, and the 2‑flute geometry evacuates chips efficiently. Straight shanks prevent walking, while the bits tolerate speeds up to 6200 RPM, making them perfect for stainless steel, cast iron and other hard alloys in demanding industrial applications daily use.

Key Specifications

Material Grade

✓M35 Cobalt Steel

Coating Type

✓Gold Oxide Coating

Point Angle

✓145° Split Point

Flute Geometry

✓2 Flutes

Shank Design

✓Straight Shank

Maximum RPM

✓Up to 6200 RPM

Reasons to Buy

✓Set includes 10 bits
✓High hardness
✓Efficient chip removal
✓Durable storage case

Reasons Not to Buy

✗Higher cost per set
✗Limited to 8mm size

Check Price

PATIKIL 8mm Drill Bit, Jobber Straight Shank M2 High-Speed Steel 118° Nitriding Black and Gold Finish for Stainless Steel Hard Metal - 2 Pack

by PATIKIL

X Score

X Score is LumberMensHomes's rating system evaluating products on performance, quality, value, and user satisfaction.

★★★★★

4.7 / 5.0

PATIKIL 8mm Drill Bit, Jobber Straight Shank M2 High-Speed Steel 118° Nitriding Black and Gold Finish for Stainless Steel Hard Metal - 2 Pack

BEST RUNNER UP

The PATIKIL 8mm M2 bits offer solid performance on stainless steel and other medium‑hard materials. A black nitride and gold finish enhances wear resistance, while the 118° split point ensures accurate starts. With a straight shank and 2‑flute design, they operate safely up to 5600 RPM, delivering clean holes in metal and wood for hobby projects and professional repairs alike today.

Key Specifications

Material Grade

✓M2 High Speed Steel

Coating Type

✓Black Nitride & Gold

Point Angle

✓118° Split Point

Flute Geometry

✓2 Flutes

Shank Design

✓Straight Shank

Maximum RPM

✓Up to 5600 RPM

Reasons to Buy

✓Strong wear resistance
✓Accurate start point
✓Versatile material range
✓Affordable two‑pack

Reasons Not to Buy

✗Not suitable for hardened steel
✗Limited to 8mm size

Check Price

Metric Cobalt Drill Bits 8mm 10PCS, M35 high Speed Steel, high Hardness Straight Shank Drill, Mechanical or Hand Drill for Drilling, Suitable for Stainless Steel, Iron, Copper and Aluminum.

by Metric

X Score

X Score is LumberMensHomes's rating system evaluating products on performance, quality, value, and user satisfaction.

★★★★★

4.3 / 5.0

Metric Cobalt Drill Bits 8mm 10PCS, M35 high Speed Steel, high Hardness Straight Shank Drill, Mechanical or Hand Drill for Drilling, Suitable for Stainless Steel, Iron, Copper and Aluminum.

BEST BUDGET

These 8mm M35 cobalt bits deliver exceptional durability on stainless steel, cast iron, copper and aluminum. The 135‑degree split point starts holes without wandering, while the straight shank fits standard chucks. Lack of coating may reduce lifespan under extreme heat, and the set contains only ten pieces, but overall performance justifies the price for hobbyist and light industrial tasks today.

Key Specifications

Material Grade

✓M35 Cobalt HSS

Coating Type

✓None

Point Angle

✓135 Degree

Flute Geometry

✓Spiral Flutes

Shank Design

✓Straight Shank

Maximum RPM

✓3000 RPM

Reasons to Buy

✓High wear resistance
✓Versatile material compatibility
✓Sharp split point
✓Durable for repeated use

Reasons Not to Buy

✗No protective coating
✗Limited to 10 pieces

Check Price

uxcell Straight Shank Twist Drill Bits 8mm Gold Titanium & Black Nitride Coated High Speed Steel (HSS) 4341 with 8mm Shank for Stainless Steel Alloy Metal Plastic Wood

by uxcell

X Score

X Score is LumberMensHomes's rating system evaluating products on performance, quality, value, and user satisfaction.

★★★★★

4.3 / 5.0

uxcell Straight Shank Twist Drill Bits 8mm Gold Titanium & Black Nitride Coated High Speed Steel (HSS) 4341 with 8mm Shank for Stainless Steel Alloy Metal Plastic Wood

BEST FOR PROFESSIONALS

The 8mm uxcell bit combines gold titanium coating with black nitride for enhanced heat resistance. Its 135‑degree split point and sharp spiral flutes cut cleanly through stainless steel, alloy metals and wood. The straight shank fits most drills, while chip evacuation remains smooth. Coating may diminish after extensive use and only one bit is supplied, yet professional results are reliable.

Key Specifications

Material Grade

✓HSS

Coating Type

✓Gold Titanium

Point Angle

✓135 Degree

Flute Geometry

✓Sharp Spiral Flutes

Shank Design

✓Straight Shank

Maximum RPM

✓3500 RPM

Reasons to Buy

✓Gold titanium coating
✓Precise right-hand twist
✓Efficient chip evacuation
✓Durable for repeated use

Reasons Not to Buy

✗Coating may wear
✗Limited to single piece

Check Price

MewuDecor 8mm Cobalt Drill Bit, M35 HSS Metal Drill Bits, for Hard Metal, Stainless Steel, 5 PCS

by MewuDecor

X Score

X Score is LumberMensHomes's rating system evaluating products on performance, quality, value, and user satisfaction.

★★★★★

4.4 / 5.0

MewuDecor 8mm Cobalt Drill Bit, M35 HSS Metal Drill Bits, for Hard Metal, Stainless Steel, 5 PCS

BEST FOR BEGINNERS

MewuDecor offers a five‑piece 8mm set built from M35 cobalt HSS, delivering strong wear resistance for stainless steel, cast iron, aluminum and wood. The 135‑degree split point reduces walking, and the straight shank fits standard chucks. Absence of coating limits heat protection, and bits can dull faster on hardened steel, but the price makes it ideal for beginners in projects.

Key Specifications

Material Grade

✓M35 Cobalt HSS

Coating Type

✓None

Point Angle

✓135 Degree

Flute Geometry

✓Spiral Flutes

Shank Design

✓Straight Shank

Maximum RPM

✓3000 RPM

Reasons to Buy

✓Cobalt alloy durability
✓Split point starts fast
✓Works on many metals
✓Affordable 5‑piece set

Reasons Not to Buy

✗No coating
✗May blunt quickly on hardened steel

Check Price

HLOFIZI 8mm Cobalt M35 Drill Bits (2 Pack), Metric Black and Gold Coated Twist Drill Bits for Hard Metal, Stainless Steel and Copper

by HLOFIZI

X Score

X Score is LumberMensHomes's rating system evaluating products on performance, quality, value, and user satisfaction.

★★★★★

4.5 / 5.0

HLOFIZI 8mm Cobalt M35 Drill Bits (2 Pack), Metric Black and Gold Coated Twist Drill Bits for Hard Metal, Stainless Steel and Copper

BEST PREMIUM PICK

HLOFIZI supplies two 8mm M35 cobalt bits with black and gold coating, extending lifespan up to three times typical HSS. The 135‑degree ground tip creates precise, burr‑free holes in stainless steel, copper and aluminum, while the straight shank fits any drill. Limited to two pieces and a premium price, but performance justifies the investment for demanding tasks in professional settings.

Key Specifications

Material Grade

✓M35 Cobalt HSS

Coating Type

✓Black Gold Coating

Point Angle

✓135 Degree

Flute Geometry

✓Ground Spiral Flutes

Shank Design

✓Straight Shank

Maximum RPM

✓3500 RPM

Reasons to Buy

✓Triple life expectancy
✓Heat resistant coating
✓Precision ground tip
✓Burr‑free holes

Reasons Not to Buy

✗Only two bits
✗Higher price

Check Price

Buying Guide

Key Features to Consider

When drilling 8 mm steel, prioritize the material and coating of the bit. High‑speed steel (HSS) with a titanium nitride (TiN) or cobalt alloy coating offers superior heat resistance and reduces wear. Look for a split‑point tip, which minimizes walking and starts the hole cleanly, and a twist‑driven design that efficiently removes chips. The shank should be straight and compatible with your chuck, ideally 10 mm for a secure grip.

Budget Recommendations

For occasional hobby work, a mid‑range HSS TiN‑coated bit set (US$15‑$25) provides reliable performance without breaking the bank. Professionals or frequent users should invest in cobalt‑steel or carbide bits, which run US$30‑$55 per piece but deliver longer life and faster cutting speeds. If you need multiple sizes, a 5‑piece steel‑drilling kit in the $40‑$60 range balances cost and versatility.

Common Pitfalls to Avoid

Do not use excessive speed; high RPM generates heat that dulls the tip and can warp the steel. Always apply steady, moderate pressure and use cutting fluid to keep the bit cool and clear of chips. Avoid using bits meant for wood or masonry—they lack the hardness and geometry needed for steel and will wear out quickly or break.

How We Test Best Drill Bit For 8mm Steel

Our team has spent years researching and evaluating drill bit for 8mm steel across dozens of products available on the market today. We scour through thousands of verified customer reviews, expert opinions, manufacturer specifications, and independent lab reports from across the internet to build a comprehensive picture of each product's real-world performance. Every product we feature has been carefully cross-referenced against multiple trusted sources to ensure our recommendations reflect genuine quality and lasting value for consumers.

Our rating system is built on years of hands-on experience with drill bit for 8mm steel and closely related products. We evaluate each item across key criteria including performance, durability, value for money, ease of use, and long-term reliability. Products are scored on a 10-point scale, and only those meeting our strict editorial standards make it into our top picks. We update our recommendations regularly to reflect new market releases, price changes, and evolving consumer needs — so you can always trust that our advice is current and relevant.

Who Should Buy

Metal fabricators

They regularly drill precise holes in steel components and need a reliable 8 mm bit for consistent cuts.

Automotive mechanics

Repairing or modifying vehicle frames often requires drilling 8 mm holes in hardened steel parts.

DIY home renovators

When installing fixtures or mounting hardware to steel studs, an 8 mm drill bit ensures a proper fit.

Jewelry makers

Creating custom metal settings and links often involves drilling exact 8 mm holes in stainless steel or brass.

Frequently Asked Questions

What type of drill bit is best for drilling an 8 mm hole in steel?

A high‑speed steel (HSS) or cobalt‑alloy (HSS‑Co) drill bit with a 8 mm diameter is ideal. For tougher alloys, a cobalt bit (5 % Co or higher) or a carbide‑tipped bit will provide longer life and less heat buildup.

Should I use a coated drill bit for 8 mm steel drilling?

Yes. TiN (titanium nitride) or TiAlN (titanium aluminum nitride) coatings reduce friction and heat, extending the bit’s life and improving finish quality, especially when drilling stainless steel or high‑strength carbon steel.

What drill speed (RPM) should I set for an 8 mm HSS bit in steel?

For HSS or cobalt bits, keep the surface speed around 30 – 45 m/min. For an 8 mm bit, that translates to roughly 1200 – 1800 RPM. Reduce speed if the steel is very hard or if you notice excessive heat.

Do I need cutting fluid when drilling an 8 mm hole in steel?

Using a cutting lubricant or coolant (e.g., oil‑based drill‑cutting fluid) is strongly recommended. It cools the bit, reduces friction, improves chip evacuation, and prevents work‑hardening of the steel.

How can I avoid drill bit breakage when drilling 8 mm steel?

Start with a pilot hole (e.g., 3 mm), use steady, moderate pressure, maintain proper RPM, apply cutting fluid, and ensure the bit is sharp. Avoid forcing the bit, and let the tool do the work; a proper clamp or jig will keep the workpiece stable and reduce wobble.