Cast iron pipes were used long ago and can still be found in older buildings and homes.

They were used before other types of piping were invented and made available. Many older properties even today still have drainpipes that are cast iron. If you need to replace older cast iron pipes, it will be important that you know how to cut them for removal. 

Several kinds of tools and instruments can be used to cut. Among these we find:

• Angle Grinder
• Cold chisel
• Hacksaw
• Reciprocating saw
• Snap cutter
• Inside pipe cutter

Cutting Cast Iron Pipe Using a Snap Cutter

Necessary Tools

• Chalk or crayon
• Snap cutter

Step 1: Marking the Pipe 

Decide where you wish to cut the cast iron pipe. Using a crayon or chalk, draw a line onto the pipe. Try to draw your line as straight as possible on the pipe. You can wrap the pipe with a paper sheet. Now try drawing along the edge to keep your line straight.

Tip: You may need pipe supports. Long horizontal pipes will need supports at least every five feet. Long vertical pipes may need riser clamps placed at floor levels. These clamps will attach to the floor structure or into blocks of wood attached to walls. Cast iron pipe should not be left unsupported.

Step 2: Prepare the Snap Cutter

Take the snap cutter and wrap the cutting chain of the cutter around the cast iron pipe and latch the chain. The chain needs to be positioned as evenly as possible. As many cutting wheels as possible must be placed against the pipe surface. Adjust the chain so it is snug.

Step 3: Press the Ratchet Lever

Place pressure on the snap cutter lever to pump. In this way, the wheels will tighten and cut into the pipe. It may be necessary to score the pipe a few times before completing the final cut.

Step 4: Complete the Cut

Continue cranking until the pipe cuts through.  The pipe will snap with a loud popping noise.

Step 5: Repeat the Process

To remove the pipe, you will need to cut it in at least two places. Repeat the steps to cut the pipe along all chalk lines.

Tip: If you are cutting cast iron pipe that lays on a worktable or on the ground, you may need to slightly rotate your cast iron pipe before completing the final cut. It will also be necessary to measure the pipe length that you desire.

Cut Cast Iron Pipe with a Hacksaw

Even though a hacksaw is an inexpensive option for cutting piping and you probably have one in your toolbox, cast iron is a very hard material. So, you will most likely need several replacement blades to be able to complete cuts. It also is one of the slowest procedures to apply and the most physically taxing.

Necessary Tools

• Chalk or crayon
• Hacksaw
• Extra replacement blades

Step 1: Measure and Mark.

If you are cutting a free piece of pipe on your workbench, measure the length you need and mark it with chalk or crayon. If you are removing a cast iron pipe, mark it where you need to cut it with a piece of chalk. Also, try to mark lines that are straight. Wrap the pipe with a paper sheet. Trace a line along its edge.

Step 2: Position the hacksaw.

Place the hacksaw onto the chalk line on the pipe.

Step 3: Cut the pipe

Begin sawing the pipe back and forth on the chalk line. Exert sufficient force to penetrate the pipe and continue sawing.

Tip: If necessary, change the saw blade when it wears down.

Step 4: Repeat the steps

Repeat the sawing along other chalk lines that you have prepared.

Step 5: Complete.

Once you have sawed through the chalk lines, remove the piece of pipe.

A Cold Chisel for Cutting Cast Iron Pipe

This is the other manual method used to cut cast iron pipes. It requires a certain skill level and experience to achieve success. You will also require space and access to the entire pipe from all sides.

Necessary Tools

• Chalk or crayon
• Chisel
• Ball-peen hammer

Step 1: Mark the pipe

Using chalk or a crayon, trace a straight line on the pipe where you wish to cut.

Step 2: Proceed to make small cuts

Using the chisel and hammer, make small cuts along the line around the entire circumference of the pipe.

Step 3: Break the pipe.

Continue making small cuts along the line completely around the pipe’s circumference until you are able to break the pipe along the line of the cuts with the tap of your hammer.

Cut Cast Iron with an Angle Grinder

This is a great option if you have limited space to cut in.  

Necessary Tools

• Safety glasses and gloves
• Angle grinder with a diamond blade or cut off wheel
• Chalk or crayon
• Flame-resistant material

Step 1: Protection

Put on your PPE and covering any surrounding area, objects, or materials, that are at risk of burning due to sarks from your angle grinder.

Step 2: Mark

Trace a straight line around the pipe where you wish to cut with chalk or crayon.

Step 3: Cut

Gripping your angle grinder firmly, turn it on, and begin to cut along the line marked on the pipe. Cut around the pipe’s entire circumference until cut through.

Use a Reciprocating Saw to Cut Cast iron Pipe

Necessary Tools

• Reciprocating saw
• Chalk or crayon 
• Extra blades

Step 1: Mark

Trace a straight line around the pipe’s circumference to cut it at the desired spot. Do this with chalk or crayon.

Step 2: Position the Blade

Align the blade of your reciprocating saw with the line marked on the pipe.

Step 3: Cut

Begin to cut along the line using moderate velocity. Do not attempt to cut rapidly as your blade may overheat causing it to snap.

Tip: You can add a little cold water as you cut to keep your saw blade cool.

Step 4: Complete

Cut moving the saw from one side to the other until the pipe has been cut through completely.

Cutting Cast Iron Pipe from the Inside

Necessary Tools

• PPE safety glasses
• Snug-fitting work gloves
• Hand drill
• Inside pipe cutter
• Reamer

Step 1: Preparation

Wear your PPE. Place the inside pipe cutter into the hand drill chuck and tighten. 

Step 2: Position the Cutter within the Pipe

Insert the cutter inside the pipe.

Step 3: Rotate the inside pipe cutter

In a circular motion, rotate the drill around the inside of the pipe to cut.

Step 4: Proceed with the cut

Continue this movement until you have cut the pipe through entirely.

Step 5: Clean

Remove the pipe piece that has been cut through. Using a reamer, clean the cut edge of the newly cut pipe.

The Bottom Line

Cast iron pipes can be cut efficiently using a variety of procedures.

Depending on the tools you have available, your project, and your experience level, you can choose the best method for cutting your cast iron pipes. Our detailed guide provides you with the necessary information for several of these procedures so you can choose the best method to cut your cast iron pipe.