Can You Drill Through Cast Iron? [Risky Or Safe?]

From making plowshares to steel-framed skyscrapers, cast iron has made a successful journey as an effective and sturdy metal.

For being a cheap yet useful Engineering material, cast iron is commonly used in modern-day homes worldwide.

But there might be a time when you will need to drill a hole through cast iron to attach something or for other purposes.

And because of the hardness of the metal, there is a popular question on ‘Can you drill through cast iron?’

The straightforward answer to the question is Yes, you can drill through cast iron.

But before making any attempt to do this, you should know some additional required information to avoid unwanted messes.

Without further ado, let’s jump into the details!

Things You Will Need To Drill Through Cast Iron

Make sure you have managed the following things before drilling holes in cast iron.

• A drill
• Drill bits
• Protective goggles
• Effective work gloves
• Suitable clothing for safety

Basically, drill bits need much more attention while cutting through cast iron. There might be possibilities of breaking drill bits due to the hardness of cast iron.

But cast iron is much more brittle when compared to other metals. So drilling a hole through this metal is not so tough as it seems. But you must be watchful about the debris.

Any type of drill bit for metal will go for this job.

Several types of drill bits are available in the market. Among them, cobalt steel and black oxide are famous for their durability and proper functionality.

With black oxide drill bits, you can reduce the number of metal shavings that are stuck in the cast iron after successfully drilling a hole. And a cobalt steel drill bit is so tough that breaking it on cast iron is seemingly impossible. Most importantly, these drill bits won’t get dull quickly while drilling.

If you want to step up your game, then you should go with a drill bit that has a special coating of titanium nitride aka TiN. The specialty of the drill bit is it is heat resistant and performs better friction. According to the manufacturer’s claim, a titanium nitride-coated drill bit has six times more longevity than other standard drill bits. 

Needless to say, wearing goggles while drilling will not only protect your eyes but also your ears. So choose safety glasses that can wrap over the sides of your face for providing maximum protection.

Working gloves are equally important to get the job done correctly. So pick a pair of durable gloves that is anti-slip and can save you from potential danger.

For additional safety try to put on a work jacket.

Now you are completely ready, right? Let’s move to the main part.

The Step By Step Process Of Drilling Through Cast Iron

Now you have got all the necessary tools. Now we will show you how to drill through cast iron.  Just follow the below steps consecutively to know how to drill cast iron and perform the steps thoroughly.

Step 1: Lubricate the drill bit

If you are going to make more than two holes, then lubricating the drill bit will give you surprising results. Lubricants help metal bits drill smoothly and hold the metal debris firmly so that they can’t fall away from the bits. But if you need one or two holes, you don’t have to use any lubricant. Because the self-lubricated nature of cast iron will be enough to perform the task.

Step 2: Make an indent or dimple

Now measure and mark the area where you are going to make the hole. Since a drill bit has a tendency of flying during drilling, the indent can help the drill bit to stay on course. For making the dimple, use a hammer and center punch.

When you start drilling, this dimple will give the tip of your drill bit the place to ride in.

Step 3: Select right drill bits

Selecting the right type of drill bit is very important. But you don’t have to go far and wide to find the perfect drill bits. Although all drill bits are not suitable to drill through cast iron.

You should not use any drill bits that are designed for wood and masonry. Because they will get destroyed by the cast iron for the hardness of the metal. Some other drill bits you should avoid are: 

• Forstner Bits
• Spade Bits
• Auger Bits

On the contrary, the best drill bits to cut through cast iron are cobalt bits and titanium nitride coated bits. But any high-speed metal bit should work fine on the cast iron.

Step 4: Use a table vice

To hold both sides of the material, you should use a table vice. But if the cast iron is attached to a fixed object, then it is already braced. So you don’t need to use any table vice to brace it.

Step 5: Start drilling slowly against the premade indent

If you are unsure and afraid of making any mistakes, then start drilling with a small drill bit. It would be best to do it a few times to avoid a big mess that might have occurred due to the use of a big drill bit.

The highest drilling speed of soft cast iron is 150 SFM( Surface Feet Per Minute). In order to drill a 1 to 2 inches hole on hard cast iron, the maximum drill speed should be 573 rpm (Revolutions Per Minute).

Step 6: Pull back the drill slowly

Once you have finished drilling, pull the drill back and forth so that the hole can get deburred removing all debris from it.

Step 7: Cleanse the surface and the hole

Use a dry and wet cloth to rinse completely the surface and holes. Because if any residues are left behind, it can cause serious harm. Moreover, it will prevent the secure bond of your expected object.

Final Thought

By the time you have known that drilling through cast iron is not so difficult. All you need is to follow the aforementioned steps and take necessary safety measures. 

Cast iron has become a popular material for home projects due to its versatile usage.

The toughness and heat resistance of cast iron lets you drill it without much effort.

Now you can stop asking how to drill holes in cast iron.