Cutting Cast Iron: Techniques, Tools, and Safety Measures

Cutting cast iron pipework can be complicated, especially when working in a confined space. 

However, as with many things, the once intimidating task becomes a lot simpler when you’re armed with the right tool for the job. For this one, it’s the angle grinder that fits the bill!

Traditionally, you could use a reciprocating saw or hacksaw to cut through cast iron tediously. With the introduction of an angle grinder, you can cut segments of cast iron pipe off cleanly! 

In this article, we’ll discuss: 

  • The efficiency of using an angle grinder for cutting cast iron
  • The associated techniques, tools, and safety measures you need to be aware of. 

Let’s get into it!

Cutting Cast Iron with the Angle Grinder

Angle Grinder 

The angle grinder is sturdy, and its various cutting discs can equip you for any heavy-duty challenge. 

However, if you’re looking to cut through cast iron piping with a cheaper angle grinder, it might be time to consider an upgrade. 

Nonetheless, if you’ve invested in a quality and sturdy grinder, you’ll be ready to cut through any rigid materials — even cast iron. 

You’ll need to attach a high-quality cutoff wheel to the angle grinder. Better yet, a diamond wheel would be ideal.

Cutting a cast iron pipe with an angle grinder is simple! However, before you begin cutting, ensure you have the following PPE items: 

  • A sturdy and thick pair of work gloves 
  • P2 or P3 respirator safety mask
  • Wrap-around safety glasses 
  • Flame-resistant long-sleeve shirt
  • Steel-capped safety boots.

When you’re ready to begin cutting the cast iron, the recommended and most successful method would be on a sturdy workbench with the pipework firmly seated in a bench vice. 

Once all your materials are gathered and you’ve figured out your workstation, you can begin making cuts. 

This process is intuitive and relatively straightforward. Just ensure you’re always following the instructions below to keep yourself safe:

  • Fit the cutoff or diamond wheel to the angle grinder 
  • Mark the pipework with some chalk to identify the section of cast iron to cut.
  • Put the correct protective gear around your eyes, ears, and hands
  • Secure the cast iron by using a workbench vice or a riser clamp. If you’re using a riser clamp, ensure it is positioned above any supporting points to ensure the cast iron doesn’t fall out of place
  • Turn on the grinder and work around the pipe’s marked section
  • Once a groove has been created around the pipe, allow the grinder to penetrate through a single point
  • Work around the entire perimeter from the penetration point, and work around the pipe until the cut has finished
  • If necessary, use a cold chisel to snap the pipe off completely
  • Repeat the above steps as many times as required to complete the job. 

Reciprocating Saw Blade for Cast Iron 

While the angle grinder is an excellent method for effectively cutting through any cast iron pipework, there is another method through using reciprocating saw blades

Both these tools can cut through any cast iron you may find. However, the reciprocating saw is more powerful and will do the job much quicker!

Before you begin the job using a reciprocating saw, ensure it is equipped with a fine carbide-tipped or high-quality diamond blade. 

Carbide blades don’t have teeth like a traditional blade. Instead, they have an abrasive strip perfect for hard materials like cast iron. These blades will mean you’ll have no difficulty slicing through cast iron up to 9 inches thick. 

Best Grinder Blade for Cast Iron 

Best Grinder Blade for Cast Iron

When cutting through cast iron, the blade selection is crucial. A 4.5-inch metal diamond cutting blade for angle grinders is the most recommended blade for a vicious job. These blades can cut fast and efficiently and also can cut through concrete, masonry, stone, and steel. 

However, when you’re working in tight places where the grinder cannot be used, it is recommended to use a reciprocating saw with either a diamond or carbide-grid blade. 

These blades should be 8 inches long, ¾ inches wide, and 0.03 inches thick. These blades are great options, but they don’t work as quickly. 

How Do You Cut Cast Iron Pipe in a Tight Space? 

If you’ve ever tried it before, you’ll know that cast iron pipes can be in some of the most challenging locations you’ll find around your home. 

As such, cutting through these pipes may be tough – but not impossible!

If you find yourself in a tight space, it is recommended not to use an angle grinder. These tools produce a ton of sparks, which is typically safer to work with when constrained in a tight working environment. 

Instead, a reciprocating saw is recommended to cut through cast iron while working in a confined space. 

You can easily make the necessary cuts through the cast iron by attaching a carbide-tipped or diamond blade to the saw. This also means you’ll be able to operate within the space, as no hazardous sparks will be created. 

Cutting a Cast Iron Pipe With a Reciprocating Saw 

The instructions on cutting cast iron pipe with a reciprocating saw, whether with a diamond blade or carbide-tipped blade, are outlined below:

  • For blade lubrication and to prevent wear, spray the cast iron pipework with WD-40
  • Attach the heavy-duty diamond blade or carbide-tipped blade to the reciprocating saw, ensuring it is secure
  • Simply mark the section of pipe where you’ll be cutting with a piece of chalk to make a clear and clean cut
  • Begin cutting the pipe slowly and steadily while applying light-to-moderate pressure
  • Continuing this motion until the entire pipe has been cut through with a single clean slice. A clean and even cut should allow a new coupling to be seated neatly. 

Cutting a Cast Iron Pipe With a Soil Pipe Cutter 

Using a snap cutter is a plumber’s favorite method when cutting cast iron piping. The ratchet soil pipe cutter is the most common and associated instructions are outlined below:

  • A clear path of access to the pipe that is being cut is essential. Ensure all cables are removed or out of the way
  • Take the soil pipe cutter and place the jaws square around the pipe, ensuring both hooks are placed on the pope with the open side facing up
  • Keep pulling on the open end of the chain – the one that wraps around the pipe – and do so as firmly as you can. While you’re doing this, insert the closest pin into the hook and then secure it into place before beginning the cut
  • Always ensure that the jaws of the pipe cutter are square to the pipe and the chain is aligned precisely where the first cut line was formed
  • Now that the chain is secured correctly on the pipe, rotate the ratchet clockwise to tighten the jaws
  • With as much force as possible, while rotating, a point will be reached where the pressure applied snaps the pipe with a clean cut. 


This article highlights the efficiency of using an angle grinder, reciprocating saw, and soil pipe cutter for slicing through cast iron pipes. 

The efficiency of these three methods has been investigated, and all have their strengths depending on the working conditions and scenarios.

All the tools in the article offer excellent options for effectively cutting cast iron pipe. 

Ultimately, the choice depends on the specific job! At the end of the day, the most effective method may still be to use the angle grinder with a high-quality cutoff or diamond wheel.

Photo of author

Barry Gray

Hi, I’m Barry. I’ve loved woodworking and bringing things back to life for more years than I care to remember. I hope my passion for tools comes across loud and clear in everything you read here on The Tool Square.