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SaleBestseller No. 1 −27%
BOSCH CO14B 14-Piece Assorted Set with Included Case - Cobalt M42 Metal Drill Bits with Three-Flat Shank for Drilling Applications in Stainless Steel, Cast Iron, Titanium, and Light-Gauge Metal
Bestseller No. 2
amoolo Cobalt Drill Bit Set (1/16"-1/4",13 Pcs), M35 HSS Metal Drill Bits for Steel, Stainless Steel, Hard Metal, Cast Iron, Plastic and Wood
Bestseller No. 3
COMOWARE Cobalt Drill Bit Set- 15Pcs M35 High Speed Steel Twist Jobber Length for Hardened Metal, Stainless Steel, Cast Iron and Wood Plastic with Indexed Storage Case, 1/16"-3/8"
SaleBestseller No. 4 −25%
STROTON Cobalt Drill Bit Set (1/16-1/2 Inch, 17PCS), M35 High Speed Steel Twist Drill Bits for Stainless Steel, Hard Metal, Cast Iron, Plastic and Wood
SaleBestseller No. 5 −15%
GMTOOLS 15Pcs Cobalt Drill Bit Set, M35 HSS, 135 Degree Tip, Twist Jobber Length Drill Bit Kit for Hardened Metal, Cast Iron, Stainless Steel, Plastic and Wood, with Indexed Storage Case 1/16"-3/8"
SaleBestseller No. 6 −22%
STROTON Cobalt Drill Bit Set (1/16-1/4 Inch, 13PCS), M35 High Speed Steel Twist Drill Bits for Stainless Steel, Hard Metal, Cast Iron, Plastic and Wood
SaleBestseller No. 7 −8%
YOUGFIN 29 Pieces Drill Bits, High Speed Steel with Black and Gold Finish, Carbide Twist Drill Bit Set for Hardened Metal, Stainless Steel, Cast Iron with Indexed Storage Case, 1/16 Inch-1/2 Inch
Bestseller No. 8
Luckyway 5-Piece 1/2" M35 Cobalt Drill Bits, Jobber Length Twist Drill Bit Set for Hard Metal, Stainless Steel, Cast Iron, Wood and Plastic, with Storage Case
Bestseller No. 9
ROGAPER Cobalt Drill Bit Set, 29Pcs M35 HSS Twist Jobber Length for Hardened Metal, Stainless Steel, Cast Iron, Wood and Plastics, 1/16" - 1/2"
Bestseller No. 10
DelitonGude 9/32 inch HSS M35 Cobalt Twist Drill Bits,High Speed Steel,Pack of 5,Suitable for Steels,Cast Iron,Stainless Steels and Other hardMetals(9/32inch)


Drilling into cast iron requires precision and durability, given the material’s hardness and brittleness. Cast iron, widely used in manufacturing, construction, and even cookware, demands drill bits that can withstand its abrasive nature without dulling quickly or causing damage to the workpiece. The right drill bits not only make the job easier but also ensure clean, accurate holes. With various types and materials of drill bits available, selecting the best ones for drilling into cast iron requires understanding your specific needs and the features that will best suit your tasks. This guide will provide you with essential considerations to help you select the best drill bits for cast iron.

Key Features to Consider


  • High-Speed Steel (HSS): Offers good durability and is suitable for drilling into softer cast iron. Can be used for general-purpose drilling.
  • Cobalt (Co): Provides superior heat resistance and longevity, ideal for drilling into harder grades of cast iron and for prolonged use.
  • Carbide-Tipped: Offers the highest hardness and heat resistance, best for professional use in industrial applications involving cast iron.

Bit Type

  • Twist Drill Bits: The most common type, suitable for a wide range of drilling tasks, including into cast iron.
  • Cobalt Drill Bits: Specifically designed for drilling into harder metals, including stainless steel and cast iron, due to their high heat resistance.


  • Black Oxide: Increases wear resistance and reduces friction, suitable for drilling into softer cast iron.
  • Titanium Nitride (TiN): Extends the life of the drill bit and increases drilling speed, though may not be as effective on harder cast iron as cobalt or carbide bits.

Point Angle

  • 135-degree Split Point: Reduces “walking” or slipping at the start of drilling, ideal for precise drilling on hard surfaces like cast iron.
  • 118-degree Point: Standard angle suitable for softer materials but may still be used on cast iron with careful operation.

Flute Design

  • Parabolic Flute Design: Offers better chip removal, reducing the risk of clogging and overheating when drilling into cast iron.

Shank Type

  • Round Shank: Fits most standard drills but may slip under high torque.
  • Hex Shank: Provides a better grip, reducing the chance of slipping, especially in high-torque applications.

Pros and Cons

Pros of Cast Iron Drill BitsCons of Cast Iron Drill Bits
✔️ Designed to withstand the hardness and abrasiveness of cast iron❌ High-quality materials like cobalt and carbide can be expensive
✔️ Specialized coatings and flute designs improve efficiency and lifespan❌ Requires careful handling and proper cooling to prevent bit damage
✔️ Various types and materials available for different cast iron drilling needs❌ Not all drill bits are suitable for all types of cast iron or thicknesses
✔️ Split point angles reduce slipping and improve accuracy❌ Drilling into cast iron can be time-consuming and requires patience

Quick Tips

  1. Assess the Hardness of the Cast Iron: Choose a drill bit material that matches the hardness of the cast iron you’re working with.
  2. Opt for Quality: Investing in higher-quality cobalt or carbide-tipped drill bits can enhance durability and performance, especially for frequent use.
  3. Use Proper Technique: Ensure adequate lubrication and use a slow, steady speed to prevent overheating and maintain bit sharpness.

Selecting the best drill bits for cast iron involves considering the material, bit type, coating, point angle, flute design, and shank type. The ideal drill bits for your projects will offer the durability, heat resistance, and precision needed to tackle the challenges of drilling into cast iron effectively. Whether you’re working on automotive parts, construction materials, or cast iron cookware, investing in the right drill bits can greatly enhance your drilling capabilities, leading to cleaner, more accurate holes and more efficient project completion.