Cast iron is a robust and durable metal. However, drilling this metal is easier than other metals due to its brittle and heat-resistant nature. As such, you need to get a drill bit that will match its strength. If not so, the cast iron will end up breaking your bit.
Unlike wood, plastic, or cement, cast iron requires you to use the best drill bit for cast iron to achieve quality results. Due to the construction industry’s growth, there are different types of drill bits in the market today. As such, finding the right drill for casting iron can be a bit daunting.
Fortunately, we’ve made your work easier by looking at the good-quality cast iron drill bits. This article includes a buyer’s guide to ensure you get the right product.
Comparison of Popular Drill Bits for Cast Iron
But first, take a look at this comparison list for the top drill bits for cast iron. You can use any of these items to drill holes into cast irons like a pro.
Review of the 11 Best Cast Iron Drill Bits on the Market
1. Hymnorq Metric Cobalt Steel M35 Drill Bits
- Material: Cobalt Steel
- Cuts through: Stainless steel, Cast iron and other metals
- Size Bits: 1mm, 1.5mm, 2mm, 2.5mm, 3mm
- Shank: Round
- Finish Type: Bronze Oxide
- Number of bits: 50 bits
The Hymnorq Metric is built from high-quality M35 cobalt. The material is a mixture of steel and cobalt, 
It has a total of 50 drill bits, and each piece has a different size. Meaning, you will have multiple bits to cut through all kinds of surfaces and materials.
Moreover, the drill bit features a 135 quick-cut tip that allows quick and smooth drilling.
- Ideal for many types of materials
- Wide range and drill bits
- Easy to use
- A bit small for some tasks
- Break often
2. POWERTEC QDB2012 Cobalt Drill Bit
- Material: Cobalt
- Cuts through: Metal, Stainless steel, Nickel alloy, Cast iron and Softer material
- Size Bits: 1/2-Inch
- Shank: Straight Shank
- Finish Type: Nickel
- Number of bits: 2 bits
The POWERTEC QDB2012 is a set of two drill bit suitable for drilling through cast iron,
Both bits are made from M35 steel that makes it sturdy and durable enough to withstand wear and heat buildup. You can use them to drill holes through metals with minimal pressure.
Another great thing about this drill bits is that they are easy to use and sharpen.
- Easy to sharpen
- Durable
- Do not break or bend
- Ideal for both keyless and keyed drills
- No carrying case
3. Bosch Cobalt M42 C014B Drill Bit Set
- Material: Stainless Steel, Cobalt
- Cuts through: Stainless Steel, Cast Iron, Titanium, Light-Gauge Metal, Aluminum
- Size Bits: 1/16″, 5/64″, 3/32″, 7/64″, 1/8″, 9/64″, 5/32″, 3/16″, 7/32″, 1/4″, 5/16″, 3/8″, 1/2″
- Shank: Straight
- Number of bits: 14 bits
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Bosch is also an excellent option since it comes with 12 drill bits, and each piece has a different size.
Also included is a high-quality carry case for easy transportation and storage.
In terms of construction, the drill beats are made from heat-resistant combat alloy for durability and maximum performance.
- Thick design for stability
- Durable
- Heat-resistant
- A bit pricy
- Brakes sometimes
4. Rannb End Mill Cutting Dia Drill Bits
- Material: Metal
- Cuts through: Carbon steel, alloy steel, die steel, tool steel, cast iron, and titanium.
- Size Bits: 3/4″×3/4″
- Shank: End Mill Bit
- Number of bits: 1 bit
Rannb End Mill Drill bit is built from high-quality steel that makes it durable and wear-resistant.
On top of that, it features a large front design that minimizes cutting resistance and increases its efficiency.
- Great design
- Tough and durable
- Smooth and fast drilling
- Easy to use
- Only one piece
5. BeHappy Cobalt Drill Bit Set
- Material: Carbide
- Cuts through: Stainless steel, Cast iron, Superalloy, Titanium alloy, hard plastic and wood
- Size Bits: 1/16″, 5/64″, 3/32″, 7/64″, 1/8″, 9/64″, 5/32″, 11/64″, 3/16″, 13/64″, 7/32″, 15/64″, 1/4″, 17/64″, 9/32″, 19/64″, 5/16″, 21/64″, 11/32″, 23/64″, 3/8″, 25/64″, 13/32″, 27/64″, 7/16″, 29/64″, 15/32″, 31/64″, 1/2
- Shank: Straight
- Number of bits: 29 bits
The next option provides 29 drill bits with different sizes.
As such, you can use them for drilling through titanium alloy and hardened steel. You can also use them to cut through soft materials.
Furthermore, the drills have a hardened cutting edge for superior sharpness.
- Ideal for rough and soft materials
- Easy to wear
- Multiple drill bits
- Smooth cutting effects
- A bit bulky
6. COMOWARE Cobalt Drill BIT Set
- Material: Cobalt
- Cuts through: Stainless steel, Cast iron, High temperature alloy, Titanium alloy, Hard plastics and woods, and also can be used for softer materials
- Size Bits: 1/16″ 2pc, 5/64″ 1pc , 3/32″ 2pc, 7/64″ 1pc, 1/8″ 2pc , 9/64″ 1pc, 5/32″ 1pc, 3/16″ 1pc, 7/32″ 1pc, 1/4″ 1pc, 5/16″ 1pc, 3/8″ 1pc
- Shank: Round
- Finish Type: Gold Oxide
- Number of bits: 15 bits
You can depend on the COMOWARE Cobalt Drill BIT Set for excellent performance
With a pilot tip of 135-degrees, the bit will allow a smooth and fast drilling process on any material.
Also included is a gold oxide layer that makes the drill bits wear and corrosion resistance for durability.
- 15 pieces available
- Highly durable
- Compact and easy to carry
- Not ideal for cutting wood and plastic
7. Amoolo 13 Pcs Cobalt Drill Bit Set
- Material: M35 Cobalt HSS
- Cuts through: Stainless steel, Cast iron, High temperature alloy, Titanium alloy, Hard plastics and woods, and also can be used for softer materials
- Size Bits:1/16″,5/64″,3/32″,7/64″,1/8″,9/64″,5/32″,11/64″,3/16″,13/64″,7/32″,15/64″,1/4″
- Shank: Round
- Tool Flute Type: Spiral
- Number of bits: 13 bits
An inclusion of cobalt and a bit of steel in the construction
With up to 13 bits, you can use this set for drilling through a wide range of surfaces and materials.
What’s more, the drills have a point split of 135 degrees that make the drilling process easy and smooth.
- Heat-resistant
- Great price
- Fast and smooth drilling experience
- Makes hole on the hardest materials
- No case included
8. Ludopam Drill Bit Set
- Material: Cobalt High Speed Steel
- Cuts through: Stainless steel, Cast iron, high temperature alloy, Titanium alloy, hard plastics and woods, and also can be used for softer materials
- Size Bits: 1/8″
- Shank: Straight
- Finish Type: Titanium
- Number of bits: 10 bits
Ludopam Drill Bit Set is also made from tough and high-speed,
Moreover, it features a twist design and a 135-degree split point that cleans debris and chips faster than regular bits.
- 10 drill bits
- Versatile
- Easy to use
- No carrying case
- Brakes easy
9. LU&MN HSS Jobber M35 Cobalt Drill Bit
- Material: High Speed Steel
- Cuts through: Stainless steel and Cast iron, and also can be used for softer materials
- Size Bits: 1/8″
- Shank: Round
- Tool Flute Type: Spiral
- Number of bits: 10 bits
Unlike regular HSS drill bit, this one offers a longer life span and more strength. Since this drill is made from quality cobalt steel, it not only provides a fast and smooth drilling performance but is also heat resistant.
You get 13 pieces, and so you can use them for a wide range of surfaces such as cast iron, stainless steel.
- Easy to carry
- Heat resistant
- Affordable price
- Too short
- Not great for stainless steel
10. SPKLINE Cobalt Drill Set
- Material: Metal
- Cuts through: Stainless steel, light-gauge metal, high-carbon steel, aluminum and alloy steel, cast iron, abrasive alloy metal, other hard metal and hardened steel
- Size Bits:1.5mm(1/16″), 2mm(5/64″), 2.5mm(3/32″), 3mm(7/64″), 3.2mm(1/8″), 3.5mm(9/64″), 4mm(5/32″), 4.5mm(11/64″), 4.8mm(3/16″), 5mm(13/64″), 5.5mm(7/32″), 6mm(15/64″), 6.5mm(1/4″)
- Shank: Straight
- Number of bits: 13 bits
SPKLINE Cobalt Drill Set is tough enough to cut through tough materials even stainless steel,
It is made from wear and heat-resistant cobalt alloy for durability.
- Versatile
- Easy to carry
- Excellent performance
- Neat holes
- A bit short
11. Mtsooning Twist Drill Bit Set
- Material: Steel
- Cuts through: Wood, Plastic, Metal
- Size Bits: 1mm 3/64″
- Shank: Straight
- Tool Flute Type: Straight
- Number of bits: 10 bits
The Mtsooning Twist Drill Bit Set is made from tough steel 
In addition, the material used provides the best combination of wear resistance, tear-resistance, and strength. It drills clean and precise holes in both light and heavy drilling jobs.
- Abrasion and heat resistant
- Multiple drill bits
- Highly durable
- Cheap carrying case
Buyer’s Guide
As we mentioned earlier, you need to get the right drill bit to drill through cast irons. There are several factors you need to consider to increase your chances of getting the right drill bit for the job.
Let us take a look.
Drill Bit Materials
The material used makes the drill bit strong and durable. Hardened steel is the best material for cutting through cast iron, stainless steel, and other sturdy metals. Steel is also resistant to wear and remains sharp for a long.
Size
We recommend short bits since they are more durable than long drill bits. Their length makes them tougher and reduces the chances of breaking. Due to their toughness, short bits are firmer and thicker. Long drills tend to break, spin, and twist easily.
Design
Drill bits come in different designs. The most common design for drilling through cast iron or any other tough metal is the split-point design. Other designs include fish-point, tapered point, and v-point. You also need to ensure that the bit is securely attached to the chunk.
FAQs
In this part of the article, we answer some of the most common questions on this topic. The informative section will give you a better understanding of the right drill bit for brittle metal.
How Do I sharpen Cast Iron Drill Bits?
You can sharpen drill bits with a metal grinder. Just hold your bit from the edge and allow the ground to sharpen it. You can either hold the metal grinder with your hand or buy a sharpening tool to get the work done.
How Often Should I Lubricate my Cast Iron Drill Bit?
You should lubricate your bit before cutting through metals. This reduces friction and promotes faster and smoother drilling. Apart from that, high-quality lubricants prolong the life of your bit. If you are drilling through plastic or wood, you don’t need to lubricate the drill bit.
What Do I do if a Drill Bit gets Stuck in Cast Iron?
If the bit gets stuck on the surface, you can remove it by rotating it anti-clockwise. You can do this using a screw/bolt remover. In case this doesn’t work, you can enter nails on the flute channels and grab them using a locking plier.
Best Overall
In the end, we choose the Hymnorq Metric Cobalt Steel M35 Drill Bit as the best pick. It is sturdy and highly resistant to wear and tear. You can also use the drill bits in hard surfaces without twisting, breaking, or bending.
You might also appreciate the fact that you get a total of 50 pieces in a single product.
Wrapping It Up
For you to dig holes through any metal, you need equipment designed for that purpose. Well, now you have all the information you need to know about drill bits for cast irons. There is a wide range of drill bits available today, so it’s essential to make an informed buying decision.