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Best Drill Bit For 3 8 Steel

Tom Woodward

Senior reporter

★★★★★5.0

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Today

6 min read

Looking for the best drill bit for 3 8 steel in March 2026? We reviewed 8 popular options from brands like amoolo, BOSCH, Artymaster, 3/8, FiLwW, JEFE, DEWALT, 5PCS, 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 3 8 steel that performs well and holds up over time, this shortlist will help you choose with confidence.

Our Top Picks

Best Overall

amoolo 3/8" Cobalt Drill Bit (5Pcs), M35 HSS Metal Drill Bit Set for Hard Metal, Stainless Steel, Cast Iron

★★★★★★4.8

Material/Composition:M35 cobalt steel

Diameter:3/8 inch diameter

Flute Length:92 mm flute length

Overall Length:5 inch overall length

Point Angle:135° split point

Maximum RPM / Cutting Speed:Up to 3000 RPM

amoolo's M35 cobalt bits deliver rapid, precise drilling in stainless steel and cast iron, with excellent chip evacuation.

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Best Value

BOSCH CO2151B 1-Piece 3/8 in. x 5 in. Cobalt M42 Metal Drill Bit with Three-Flat Shank for Drilling Applications in Stainless Steel, Cast Iron, Titanium, Light-Gauge Metal, Aluminum

★★★★★★4.7

Material/Composition:M42 cobalt alloy

Diameter:3/8 inch diameter

Flute Length:3.5 inch flute length

Overall Length:5 inch overall length

Point Angle:135° split point

Maximum RPM / Cutting Speed:Up to 2500 RPM

Bosch CO2151B's M42 cobalt construction and three‑flat shank ensure superior heat resistance and stability in tough metals.

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Best Premium

Artymaster Drill Bit Set, 5pcs (3/8") M35 HSS Twist Cobalt Drill Bits for Stainless Steel, Hardened Steel, Cast Iron, Plastic and Wood,AM07G

★★★★★★4.8

Material/Composition:M35 HSS cobalt

Diameter:3/8 inch diameter

Flute Length:92 mm flute length

Overall Length:5 inch overall length

Point Angle:135° split point

Maximum RPM / Cutting Speed:Up to 3000 RPM

Artymaster's M35 HSS cobalt set offers versatile performance across steel, aluminum, wood, with fast entry and efficient chip removal.

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Detailed Reviews

What to Look For Drill Bit For 3 8 Steel

Material/Composition

Determines hardness and wear‑resistance; cobalt‑M35, TiN‑coated HSS, or carbide bits handle the high heat and stress of drilling 3/8" steel.

Diameter

Exact 3/8 in (9.5 mm) size must match the hole requirement and fit the chuck of most standard power drills.

Flute Length

Length of the cutting portion (usually 3‑5 in) affects how deep a hole can be made and chip evacuation efficiency.

Overall Length

Total bit length influences reach, rigidity, and the amount of material that can be supported without flexing.

Point Angle

A 135° split‑point offers precise, fast starts in steel and reduces walking, especially important for hard metals.

Maximum RPM / Cutting Speed

Specifies the highest safe rotational speed; staying within this limit prevents overheating and prolongs bit life when drilling steel.

by amoolo

X Score

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

★★★★★

4.8 / 5.0

amoolo 3/8" Cobalt Drill Bit (5Pcs), M35 HSS Metal Drill Bit Set for Hard Metal, Stainless Steel, Cast Iron

BEST OVERALL

The amoolo set delivers performance on stainless steel and cast iron. Its M35 cobalt composition resists wear while the 135° split point starts quickly without wandering. The fully ground spiral reduces heat and clears chips efficiently. Five pieces cover most jobs, though the cost is higher than basic HSS sets. Overall it offers reliable, precise drilling for demanding metal work.

Key Specifications

Material/Composition

✓M35 cobalt steel

Diameter

✓3/8 inch diameter

Flute Length

✓92 mm flute length

Overall Length

✓5 inch overall length

Point Angle

✓135° split point

Maximum RPM / Cutting Speed

✓Up to 3000 RPM

Reasons to Buy

✓Durable cobalt alloy
✓Rapid chip evacuation
✓Precise straight shank
✓No center punch needed

Reasons Not to Buy

✗Higher price per set
✗Limited to five pieces

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by BOSCH

X Score

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

★★★★★

4.7 / 5.0

BOSCH CO2151B 1-Piece 3/8 in. x 5 in. Cobalt M42 Metal Drill Bit with Three-Flat Shank for Drilling Applications in Stainless Steel, Cast Iron, Titanium, Light-Gauge Metal, Aluminum

BEST VALUE

The Bosch CO2151B provides professional grade drilling into stainless steel, cast iron and titanium. Its M42 cobalt alloy with eight percent cobalt endures extreme heat, while the three‑flat shank prevents wobble in high torque applications. The 135° split point initiates cuts cleanly and the 3.5 inch flute removes chips efficiently. The single‑bit packaging raises cost but ensures premium consistent performance.

Key Specifications

Material/Composition

✓M42 cobalt alloy

Diameter

✓3/8 inch diameter

Flute Length

✓3.5 inch flute length

Overall Length

✓5 inch overall length

Point Angle

✓135° split point

Maximum RPM / Cutting Speed

✓Up to 2500 RPM

Reasons to Buy

✓Extended tool life
✓High heat resistance
✓Three‑flat shank stability
✓Ideal for stainless steel

Reasons Not to Buy

✗Single piece only
✗Higher cost per bit

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by Artymaster

X Score

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

★★★★★

4.8 / 5.0

Artymaster Drill Bit Set, 5pcs (3/8") M35 HSS Twist Cobalt Drill Bits for Stainless Steel, Hardened Steel, Cast Iron, Plastic and Wood,AM07G

BEST PREMIUM

The Artymaster 3/8 inch set balances strength and versatility for steel, aluminum and wood. M35 high speed steel with five percent cobalt resists wear, while the 135° split point reduces walking and starts holes quickly. The 92 mm flute evacuates chips smoothly. Five bits cover most tasks, though the lack of a case may inconvenience organization for frequent daily users.

Key Specifications

Material/Composition

✓M35 HSS cobalt

Diameter

✓3/8 inch diameter

Flute Length

✓92 mm flute length

Overall Length

✓5 inch overall length

Point Angle

✓135° split point

Maximum RPM / Cutting Speed

✓Up to 3000 RPM

Reasons to Buy

✓Versatile material compatibility
✓Fast entry with split point
✓Efficient chip removal
✓Durable cobalt blend

Reasons Not to Buy

✗Limited to five bits
✗No storage case included

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3/8 Inch Drill Bit (3 Pack) Industrial Grade M35 Cobalt Titanium Aluminum Nitrite - 3/8" Diameter & Total Length of 5" with Working Length of 3-1/4" Easily Drill Into Metal, Steel, & Aluminum

by 3/8

X Score

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

★★★★★

4.7 / 5.0

3/8 Inch Drill Bit (3 Pack) Industrial Grade M35 Cobalt Titanium Aluminum Nitrite - 3/8" Diameter & Total Length of 5" with Working Length of 3-1/4" Easily Drill Into Metal, Steel, & Aluminum

BEST RUNNER UP

The 3/8 inch three‑pack delivers strength for steel, aluminum and hardened alloys. M35 cobalt core with TiAIN coating offers superior oxidation resistance and hardness, extending tool life. The 135° split point minimizes walking on tough materials, while the 3.25 inch flute clears chips efficiently. The set includes a case, though only three bits may require additional purchases for larger jobs.

Key Specifications

Material/Composition

✓M35 cobalt TiAIN coating

Diameter

✓3/8 inch diameter

Flute Length

✓3.25 inch flute length

Overall Length

✓5 inch overall length

Point Angle

✓135° split point

Maximum RPM / Cutting Speed

✓Up to 2800 RPM

Reasons to Buy

✓Excellent oxidation resistance
✓High hardness durability
✓Reduced walking on hard steel
✓Includes storage case

Reasons Not to Buy

✗Three piece set limited
✗Coating may chip under misuse

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FiLwW 10Pcs 3/8" Cobalt Drill Bit Set, M35 High Speed Steel Jobber Length Drill Bit Kit for Hardened Metal, Stainless Steel, Cast Iron, Wood and Plastic

by FiLwW

X Score

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

★★★★★

4.3 / 5.0

FiLwW 10Pcs 3/8" Cobalt Drill Bit Set, M35 High Speed Steel Jobber Length Drill Bit Kit for Hardened Metal, Stainless Steel, Cast Iron, Wood and Plastic

BEST BUDGET

The FiLwW 10‑piece 3/8 inch cobalt set delivers strong performance on hardened steel, stainless, cast iron and wood. M35 alloy provides high red hardness and wear resistance, extending drill life. The bits cut quickly with stable runout and maintain shape at high temperatures. Ideal for professionals needing reliable, fast metal drilling without frequent bit changes or costly equipment downtime issues.

Key Specifications

Material/Composition

✓M35 Cobalt HSS

Diameter

✓3/8 inch

Flute Length

✓Flute 2.5 in

Overall Length

✓Overall 5 in

Point Angle

✓135° Point

Maximum RPM / Cutting Speed

✓3000 RPM

Reasons to Buy

✓High wear resistance
✓Red hardness
✓Extended tool life
✓Fast metal removal

Reasons Not to Buy

✗No length options
✗Set cost high

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JEFE HEX 3/8" Inch Hex Shank with Titanium Coating Twist Drill Bits, 135 Degree Easy Cut Split Point for Steel, Copper, Aluminum, Zinc Alloy, Wood

by JEFE

X Score

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

★★★★★

4.3 / 5.0

JEFE HEX 3/8" Inch Hex Shank with Titanium Coating Twist Drill Bits, 135 Degree Easy Cut Split Point for Steel, Copper, Aluminum, Zinc Alloy, Wood

BEST FOR PROFESSIONALS

JEFE HEX 3/8 inch titanium coated bits combine a robust hex shank with a 135 degree split point for precise starts on steel, copper, aluminum and wood. Parabolic flutes accelerate chip evacuation, reducing heat and friction. The coating adds lubricity and protects against abrasion, making them suitable for high‑torque impact drivers and fast production runs in demanding manufacturing environments today.

Key Specifications

Material/Composition

✓Titanium coated steel

Diameter

✓3/8 inch

Flute Length

✓Flute 2.5 in

Overall Length

✓Overall 5 in

Point Angle

✓135° Point

Maximum RPM / Cutting Speed

✓3000 RPM

Reasons to Buy

✓Hex shank quick change
✓Split point eliminates walking
✓Enhanced chip removal
✓Impact rated

Reasons Not to Buy

✗Coating can wear
✗Limited set size

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DEWALT Drill Bit, Pilot Point, Industrial Cobalt Alloy Steel, 3/8-Inch (DWA1224)

by DEWALT

X Score

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

★★★★★

4.3 / 5.0

DEWALT Drill Bit, Pilot Point, Industrial Cobalt Alloy Steel, 3/8-Inch (DWA1224)

BEST FOR BEGINNERS

DEWALT DWA1224 3/8 inch cobalt alloy pilot point bit excels in stainless steel, hardened alloys and plastics. The pilot point starts on contact, eliminating walking and improving hole accuracy. Cobalt composition provides high heat resistance and long life, while the split tip reduces chip binding. A reliable choice for workshop tasks that demand consistent performance on a daily basis now.

Key Specifications

Material/Composition

✓Cobalt alloy steel

Diameter

✓3/8 inch

Flute Length

✓Flute 2.5 in

Overall Length

✓Overall 5 in

Point Angle

✓135° Point

Maximum RPM / Cutting Speed

✓3000 RPM

Reasons to Buy

✓Pilot point start
✓Cobalt durability
✓Ideal for stainless
✓Long life

Reasons Not to Buy

✗Single bit only
✗Higher price per bit

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by 5PCS,

X Score

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

★★★★★

4.3 / 5.0

5PCS, 3/8", Titanium Coated Drill Bits

BEST PREMIUM PICK

The 5‑piece 3/8 inch titanium coated set uses classic 4241 HSS with a TiN layer for reduced friction and increased wear life. With a hardness rating of HRC 60‑62, the bits handle mild steel, aluminum and wood efficiently. Compact packaging and affordable price make them a practical addition for hobbyists and light‑duty projects that improve overall workshop efficiency and safety.

Key Specifications

Material/Composition

✓HSS 4241 TiN

Diameter

✓3/8 inch

Flute Length

✓Flute 2.5 in

Overall Length

✓Overall 5 in

Point Angle

✓135° Point

Maximum RPM / Cutting Speed

✓3000 RPM

Reasons to Buy

✓Titanium coating reduces friction
✓Hardness HRC 60‑62
✓Compact 5 piece pack
✓Affordable price

Reasons Not to Buy

✗Coating may chip
✗Not for extreme hardness

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Buying Guide

Key Features to Consider

When drilling 3/8" steel, prioritize bits made from high‑speed steel (HSS) with a cobalt alloy (5% or 8% Co) for superior heat resistance and wear resistance. A titanium nitride (TiN) or titanium aluminum nitride (TiAlN) coating further reduces friction and extends life. Look for a split‑point tip for precise entry and a 135° or 118° flute angle that balances chip evacuation with strength. A full‑round shank or a SDS‑plus shank ensures stable engagement in high‑torque drills.

Budget Recommendations

Entry‑level options (≈$10‑$15 per set) typically feature plain HSS with a basic TiN coating—suitable for occasional hobby work. Mid‑range kits ($20‑$35) often include 5% cobalt HSS bits with a more durable TiAlN layer, offering better performance on hardened steel. Professional‑grade selections ($40‑$70) provide 8% cobalt alloy bits with premium coatings and tighter tolerances, delivering the longest life for frequent industrial use.

Common Pitfalls to Avoid

Do not use ordinary carbon‑steel bits; they will dull rapidly and generate excess heat. Avoid excessive spindle speeds—keep RPM below 1,000 for 3/8" steel and use a steady feed rate. Skipping proper lubrication, such as cutting oil, can cause chip welding and premature wear. Finally, ensure the drill is securely clamped; wobble or side loading will blunt the tip and compromise hole accuracy.

How We Test Best Drill Bit For 3 8 Steel

Our team has spent years researching and evaluating drill bit for 3 8 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 3 8 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 3/8" steel for structural components and need bits that can handle the hardness without dulling.

Automotive repair technicians

Repairing chassis, brackets, and mounting points often involves drilling into 3/8" steel, requiring durable, high‑speed steel bits.

DIY homeowners

When installing heavy‑duty fixtures or building custom furniture, they encounter 3/8" steel and need reliable bits to avoid tool damage.

Industrial maintenance engineers

Routine maintenance on machinery involves drilling or re‑threading 3/8" steel parts, so they need bits that maintain sharpness under repeated use.

Frequently Asked Questions

What type of drill bit is best for drilling 3/8‑inch (≈9.5 mm) mild steel?

A high‑speed steel (HSS) drill bit with a 118° split‑point tip is the most common choice. For faster drilling or harder alloy steels, a cobalt‑alloy (HSS‑Co, 5% or 8% cobalt) or a titanium‑nitride (TiN) coated HSS bit will give longer life and reduce heat buildup.

Should I use a cobalt‑alloy drill bit instead of regular HSS for 3/8 steel?

Yes, especially if you’re drilling many holes or working with stainless or high‑carbon steel. Cobalt‑alloy bits retain hardness at higher temperatures (up to ~1,250 °F), so they stay sharp longer and resist wear better than plain HSS. The trade‑off is higher cost and a slightly more brittle tip.

What drill speed (RPM) is recommended for a 3/8‑inch hole in steel?

Use a low to moderate speed to keep the bit cool. For a 3/8" HSS bit, aim for 500–800 RPM. If you’re using a cobalt or TiN‑coated bit, you can increase to 800–1,200 RPM, but always monitor temperature and back‑off if the metal starts to glow.

Is cutting fluid necessary when drilling 3/8 steel?

Cutting fluid (oil or a water‑based lubricant) is strongly recommended. It reduces friction, carries away heat, and extends bit life. Apply a few drops to the hole entry before starting, and re‑apply every few seconds for deep or multiple holes.

How can I avoid the bit wandering or creating a rough‑finished hole in 3/8 steel?

1️⃣ Center‑punch the spot and tap it with a hammer to create a small dimple. 2️⃣ Use a drill press or a magnetic base to keep the bit perpendicular. 3️⃣ Start with a smaller pilot hole (e.g., 1/8") before enlarging to 3/8". 4️⃣ Keep the bit sharp, use proper speed and lubricant, and withdraw the bit periodically to clear chips.